Scientific Program

Conference Series Ltd invites all the participants across the globe to attend 2nd International Conference on Applied Crystallography Chicago, USA.

Day 2 :

Keynote Forum

Paolo Scardi

University of Trento, Italy

Keynote: Static and dynamic atomic disorder in nanocrystalline systems

Time : 09:10-09:40

Crystallography 2017 International Conference Keynote Speaker Paolo Scardi photo
Biography:

Paolo Scardi is a Full Professor of Material Science and Technology and Head of the PhD School in Civil, Environmental and Mechanical Engineering at the University of Trento, Italy. He is the author of more than 250 papers and his main interest concerns diffraction and crystallography with applications to materials science. His recent work focuses on thin films and highly deformed materials, photovoltaic devices, residual stress analysis and atomistic modeling of nanocrystalline materials.

Abstract:

Much is known about the effect of size and shape of metal nanocrystals on their catalytic activity. Size effect may appear obvious for the direct relation with the total surface area exposed to the environment, whereas shape is a major factor controlling selectivity of the catalytic reaction. Palladium nanocrystals, for example, can catalyze a variety of oxidation reactions, but the yield of the process is strongly influenced by the exposed nanocrystal facets: Better O2 activation occurs on (100) than on (111) facets, for the differences in the O-O bond stretch and spin charge density. As a consequence, Pd nanocubes are much more effective than nanooctahedra in oxygen-related catalytic reactions. The different, generally lower coordination of surface atoms reflects in an excess surface energy, which in many metals gives shorter bond distances between surface atoms, causing an average shrinking of the nanoparticle. The atomic displacement influences electronic properties, leading to d-band center modification and, in general, surface properties differing from corresponding bulk materials. Change in bond distances is largest on the surface, gradually decreasing toward the nanoparticle core; therefore, the displacement field is inhomogeneous and depends on nanocrystal size and shape. In addition to the static component, dynamic displacement in nanocrystals is also peculiar: Phonon confinement arises from the finite size, capping longest possible phonon wavelengths, while additional effects are due to the amplitude of thermal vibration, changing toward the surface for the decreasing coordination. The present contribution shows how X-ray spectroscopies can shed light on the behavior of metal nanocrystals, influenced by complex relations between size, shape, surface atomic coordination and bond distances. Atomistic approaches are indispensable to go beyond the limits of traditional crystallography, clearly inappropriate to deal with small crystals. In particular, we show how X-ray diffraction, applied to powders of nanocrystals with definite shape and little size dispersion can provide detailed information on atomic disorder.

Keynote Forum

Xavier Feaugas

University of La Rochelle, France

Keynote: Hydrogen diffusion in nickel single- and poly-crystals: the effects of self-stress

Time : 09:40-10:10

Crystallography 2017 International Conference Keynote Speaker Xavier Feaugas photo
Biography:

Professor Xavier Feaugas has published over three hundred papers, and several collective books in the field of physics, mechanics and metallurgy. His research interests lie in the area of physical bases of solid plasticity and crack initiation with a focus on interactions between plasticity and surface reactivity to understand the inception of hydrogen embrittlement and stress corrosion cracking. The main research topics are: physical bases of solid plasticity and crack initiation (dislocation pattern, slip activity, slip, irreversibility, local approach of fracture …) - Interaction between plasticity and surface reactivity (dissolution, hydrogen adsorption, passivity…) -  Multi-physics modeling (ratcheting, cyclic over-hardening, hexagonal slip plasticity, thermo-kinetic modeling, polymer and composite degradation, diffusion …) - Hydrogen Embrittlement/Stress Corrosion Cracking - Crystallographic defects (dislocation, vacancy, grain-boundaries, …), length scales, internal stresses – physical and metallurgy thermodynamic. More recent trend of its works is focus on the different aspects of the interactions between the hydrogen solute and the crystallographic defects formalized in thermodynamic framework.

Abstract:

Hydrogen diffusion and trapping has an important role in solute-dependent hydrogen embrittlement in metals and metallic alloys. In spite of extensive studies, the complexity of hydrogen diffusion in solids remains a phenomenon that needs to be clarified. The effects of the grain boundaries (GBs), and several defects (dislocations, vacancies …) and their interactions with hydrogen on the mechanisms of metal damages remain a controversy. Actually, several works suggest that the grain boundaries represent preferential paths for hydrogen diffusion, and this kind of hydrogen diffusion along GBs is higher than the interstitial diffusion. However, grains and GBs contain different defects, particularly, dislocations and vacancies. These defects are able to trap hydrogen affecting the diffusion mechanisms. Although a number of theories have been proposed to describe the role of GBs for hydrogen diffusion and segregation, none of them is able to give an exact answer. In present work we report our recent works [1-5], which support the investigation of diffusion in pure nickel single crystals and poly-crystals using both an experimental approach and a thermodynamic development. We have studied at the first time some nickel single crystals. We evaluate the hydrogen diffusion and trapping mechanisms using the electrochemical permeation (EP) coupled to the thermal desorption spectroscopy (TDS). Later, we propose to screen several bi-crystals of pure nickel with different grain boundaries. For each ones, the hydrogen diffusion and segregation are studied using EP and TDS analyses. In addition, Molecular Dynamics (MD) simulations have become a useful method to comprehend the becoming of hydrogen in these types of GBs. The results allow us to associate the short-circuit diffusion and trapping phenomena to the grain boundaries and defect characters (excess volume, defects density and distribution …). In each situation, we highlight the importance of the self-stress on the processes of diffusion and segregation.

Keynote Forum

Yimei Zhu

Brookhaven National Laboratory, USA

Keynote: Disentangle phonon modes using ultrafast electron diffraction and timely-resolved electron crystallography

Time : 10:10-10:40

Crystallography 2017 International Conference Keynote Speaker Yimei Zhu photo
Biography:

Yimei Zhu is a Senior Physicist at Brookhaven National Laboratory (BNL) and Adjunct Professor at Columbia University and Stony Brook University. He has received his BS from Shanghai Jiaotong University in 1982, MS and PhD from Nagoya University in 1987. He joined BNL as an Assistant Scientist in 1988, rising through the rank to become Tenured Senior Physicist in 2002. He is the Founding Director of the Institute for Advanced Electron Microscopy and Facility Leader of the Functional Nanomaterials at BNL. His research interests include electron crystallography of condensed matter physics of strongly correlated electron systems and advanced electron microscopy including ultrafast microscopy instrumentation. He is an Inaugural Fellow of Microscopy Society of America, a Fellow of American Physical Society and a Fellow of American Association for the Advancement of Science. He has published more than 500 peer-reviewed journal articles and delivered more than 300 invited talks at international conferences.

Abstract:

Polaron transport, in which electron motion is strongly coupled to the underlying atomic lattice, is crucial to understanding the electrical conductivity in many solids. The accompanying atomic displacements are themselves coupled through phonons, but the specific phonon modes responsible for the dynamics of polaron motion have rarely been identified. In this presentation, I will first give an overview on the 2.8 MeV ultrafast electron diffraction instrument and the time resolved electron crystallography method we developed at BNL, then focus on its application to understand charge, orbital and lattice coupling and interaction in strongly correlated electron systems. A detailed example will be given on quantifying the dynamics of both electronic and atomic motion in the LaSr2Mn2O7 manganite. Using photoexcition to set the electronic system in motion, we find that Jahn-Teller-like O, La/Sr, and Mn4+ displacements dominate the lattice response and exhibit a dichotomy in behavior overshoot-and-recovery for one sub-lattice versus normal behavior for the other. This dichotomy, attributed to slow electronic relaxation, proves that polaron transport is a key process in doped manganites. Our technique with the access to high-order reflections and being sensitive to phonons promises to be applicable for specifying the nature of electron-phonon coupling in many complex materials.

Break: Networking & Refreshment Break 10:40-11:00 @ Athens
  • Speakers Session 1: Crystallography of Novel Materials | Electron Crystallography | Recent development in the X-ray studies| Crystallography Applications
Location: Conference Hall: Zurich
Speaker

Chair

Stephan Rosenkranz

Argonne National Laboratory, USA

Session Introduction

Victor Ovcharenko

International Tomography Center, Russia

Title: The difference in the P- and T-induced dynamics in breathing crystals

Time : 11:00-11:20

Speaker
Biography:

Victor Ovcharenko has his expertise in design of molecular magnets and investigation of spin transitions, “breathing crystals” and magneto-structural correlations in heterospin compounds. He developed new methods of selective synthesis of highly dimensional heterospin systems based on metal complexes with stable organic radicals, investigated magneto-structural correlations inherent in heterospin compounds, created a new type of breathing crystals and explained mechanical activity of these crystals (breathing crystals, jumping crystals, dancing crystals).

Abstract:

Reactions between the paramagnetic transition metal ions and nitroxides are convenient and effective methods for the preparation of heterospin crystals. The presence of several paramagnetic centers in heterospin molecules stirred the growing interest in their magnetic properties because these compounds are convenient objects for studying the fine distinctions in exchange interaction channels and revealing valuable magneto-structural correlations. When the temperature (or pressure) changes, the solid compounds undergo structural rearrangements accompanied by magnetic effects similar to spin crossover. The observed anomalies are caused by the reversible spatial dynamics of Jahn-Teller coordination units. The high mechanical stability of the crystals, i.e., their ability of being reversibly compressed and expanded in the temperature range of phase transition, underlies the term breathing crystals. When the cooling–heating cycles are repeated in the range 5-325 K the phase transformations of the heterospin crystals may be accompanied by deep coloring of the solid phase, which is an unusual effect. The possibility of creating spin devices whose working unit is an exchange cluster that changes multiplicity under the action of temperature, pressure, or light was discussed. The effect of a change in the external pressure on the character of the temperature dependence of the effective magnetic moment is discussed. Noteworthy, external pressure variation and temperature variation have essentially different effect on the magneto-structural correlations.

DK. Saldin

University of Wisconsin-Milwaukee, USA

Title: Structure of viruses from experimental data from an x-ray free electron laser

Time : 11:20-11:40

Speaker
Biography:

Dilano K Saldin is a Professor at the Physics Department of the University of Wisconsin-Milwaukee, where he started as a Surface Physicist, but has over the past 10 years turned his attention to the problem of structure determination in the XFEL particularly of viruses

Abstract:

The X-ray Free Electron Later (XFEL) is a brand new machine capable of delivering X-ray to a sample some 10 billion times brighter than a conventional source. The question is whether one can exploit the ultra-brightness of the source to enable structure determination of identical randomly oriented particles delivered to the beam by means of a sample delivery system specifically designed for this purpose. The particles will be delivered to the XFEL in a specially designed apparatus that delivers identical particles in random orientation. The question is whether one can determine the structure of the particles from the collection of diffraction patterns even though one does not know the precise orientation of the particle in each. We demonstrate a solution with experimental data for the icosahedral virus PR772 from an XFEL. What we exploit is the fact that the angular correlations amongst the intensities are independent of particle orientation. Consequently an average over all diffraction patterns of the angular correlation merely increases the accuracy of the angular correlation measurement. We have developed a method of extracting the X-ray diffraction volume from accurately determined angular correlations. An iterative phasing algorithm then recovers the electron density of the viruses from the diffraction volume

Speaker
Biography:

Rama S Madhurapantula is a Senior Postdoctoral Research Associate at Dr. Joseph Orgel’s research group at the Illinois Institute of Technology, USA. He is currently involved with work on the changes in molecular packing in myelin and cytoskeleton caused by traumatic brain injury and understanding stress-strain relations in the muscle tendon junction using X-ray diffraction. He also specializes in HPLC method development and has collaborated with various research groups from Chicago to develop new methods for measuring analytes in various samples.

Abstract:

The process of non-enzymatic glycosylation, i.e., glycation, is rather slow resulting in the formation of sugar-mediated crosslinks, also known as Advanced Glycation Endproducts (AGEs), within the native structure of type-I collagen. This process occurs in all animals but is accelerated in diabetics. However, the exact locations or regions of high propensity for the formation of these crosslinks within the packing structure of collagen are largely unknown, despite our knowledge of the underlying chemistry. The results obtained showed the location of possible crosslinks and correlate the effects of crosslinks to the structural and functional sites present on the D-periodic arrangement of collagen into fibrils. Prolonged treatment with iodine, as a wound disinfectant, is detrimental to the structure of collagen underlying the wound site. Diabetic patients are more prone to injuries to limb extremities. Wounded extremities are commonly amputated to prevent the spread of infection to the rest of the body followed by low dose iodine application to the wound site. We will present results to demonstrate specific disintegration of collagen fibrils in rat tail tendons from a short iodine treatment.

Speaker
Biography:

M Sithambaresan has his expertise in synthesis and characterization of transition metal complexes and single crystal studies of organic ligands and metal complexes. His works on crystal studies on ligands and metal complexes creates new pathways for improving characterization of novel complex molecules and designing of new materials with required properties to enlighten the development of sensor for medical, pharmaceutical and various other fields.

Abstract:

Non-covalent interactions (NCI) are of paramount importance in chemistry and especially in bio-disciplines since they set up the force-field scenario through which chemical species interact with each other without a significant electron sharing between them. They represent, in fact, the machinery through which molecules recognize themselves and establish how molecules will approach and eventually pack together. These kinds of weak interactions become important in determining the properties of substances and therefore we have explored some of the novel organic molecular crystals to study the non-covalent interactions and their behavioral patterns during packing of molecular crystals. Animated pictures and videos are used to explore the nature of these interactions. This study provides better understanding of various non-covalent forces such as classical and non-classical hydrogen bond, π… π, C-H…π interactions etc. thereby demonstrating the packing forces for designing novel materials having certain interesting physical properties

Thomas Hammerschmidt

Ruhr University Bochum, Germany

Title: Three parameter crystal-structure prediction for sp-d valent compounds

Time : 12:20-12:40

Speaker
Biography:

Thomas Hammerschmidt has his expertise and passion on the reliable and robust prediction of structural stability and phase stability of technologically relevant materials. In order to make direct contact to experiments, he includes finite temperature, complex microstructures and multi-component chemistry. His focus is particularly the development, implementation and application of analytic bond-order potentials for large scale atomistic simulations

Abstract:

The prediction of the crystal structure of a material from only its chemical composition is one of the key challenges in materials design. We use a cluster analysis of experimentally observed crystal structures and derive structure maps that are systematically optimized to reach high predictive power. In particular, we present a three-dimensional structure map for compounds that contain sp-block elements and transition metals in arbitrary composition. The structure map predicts the correct crystal structure with a probability of 86% and has a confidence of 98% that the correct crystal structure is among three predicted crystal structures. The three parameters that span the structure map are physically intuitive functions of the number of valence electrons, the atomic volume and the electronegativity of the constituent elements. We test the structure map against standard density-functional theory calculations for 1:1 sp-d-valent compounds and demonstrate that our three-parameter model has comparable predictive power. We show that the identified parameters are valid for off-stoichiometric compounds and they separate binary and ternary crystal-structure prototypes

Speaker
Biography:

Vesna F Mitrovic has her expertise in study of microscopic properties of materials using magnetic resonance techniques. She is a graduate of Illinois Institute of Technology and received her PhD from Northwestern University in 2001. Her thesis work was on magnetic resonance studies of high temperature superconductor. In 2003, she joined the Brown Physics Department and she was named Alfred P. Sloan Fellow in 2007 and Fellow of American Physical Society in 2015 for her pioneering contributions to NMR study of low energy excitations in emergent quantum phases.

Abstract:

Study of the combined effects of strong electronic correlations with spin-orbit coupling (SOC) represents a central issue in quantum materials research. Predicting emergent properties represents a huge theoretical problem since the presence of SOC implies that the spin is not a good quantum number. Existing theories propose the emergence of a multitude of exotic quantum phases, distinguishable by either local point symmetry breaking or local spin expectation values, even in materials with simple cubic crystal structure such as Ba2NaOsO6. Experimental tests of these theories by local probes are highly sought for. Our local measurements designed to concurrently probe spin and orbital/lattice degrees of freedom of Ba2NaOsO6 provide such tests. We show that a canted ferromagnetic phase which is preceded by local point symmetry breaking is stabilized at low temperatures as predicted by quantum theories involving multipolar spin interactions. Specifically, we find that the ferromagnetic state is in fact a type of canted ferromagnet with two sub-lattice magnetizations and that cubic symmetry breaking occurs at a temperature above the Néel temperature and it involves deformation of oxygen octahedra presumably reflecting a complicated pattern of staggered orbital order. Our findings are in startlingly good agreement with theoretical predictions based on quantum models. Thus, our results, to be presented, establish that such quantum models represent an appropriate theoretical framework for predicting emergent properties in materials with both strong correlations and SOC, in general

Break: Lunch Break 13:10-14:00 @ Athens
  • Speakers Session 2: Crystallography of Novel Materials | Electron Crystallography | Recent development in the X-ray studies| Crystallography Applications
Location: Conference Hall: Zurich
Speaker

Chair

Vijeesh P

The Cochin College, India

Session Introduction

Vijeesh P

The Cochin College, India

Title: Growth and growth rate analysis of potassium succinate –crystal

Time : 14:00-14:20

Speaker
Biography:

Vijeesh P is currently an Assistant Professor in the Department of Physics, The Cochin College and Research Scholar in Cochin University of Science and Technology. His major research area is crystallography.

Abstract:

Single crystals of potassium succinate-succinic acid were grown by slow-cooling method. The growth of the crystal is recorded using shadowgraph and the growth rate is evaluated using image processing. The growth rate analysis showed that slow cooling rate enhances the quality of crystal obtained. Also the in situ image analysis of the crystal gives a better method for controlling the growth parameters of the crystal. Semi organic non-linear optical materials play an important role in many fields of science such as information storage systems, data processing systems, information technology, telecommunication, utility equipment development, etc. Their properties like high melting point, dielectric and mechanical stability, second harmonic generation, etc. made them suitable for many applications. Semi organic non-linear materials are developed to overcome the shortcomings of organic non-linear materials such as low transparency and short optical band gap. Semi organic materials formed with ionic salts offer wide range of frequencies. Also it is much easier to grow semi organic materials. This paper presents the design and realization of a crystallizer and its use to synthesize from aqueous solution, structure, crystal growth and growth rate analysis of Potassium Succinate (KS) crystal which belongs to monoclinic system. Even though the evaporation techniques were used for the growth of KS, the slow cooling solution growth of KS is not much tried so far. This method provides comparatively easier and faster method to grow crystals. The solution growth of KS is not much represented in the literature. A crystallizer for slow cooling solution growth is designed and realized and a single crystal of potassium succinate is grown using slow cooling solution growth technique. The growth rate analysis is done by shadowgraph image analysis. The image analysis showed the growth rate of different faces of the crystal

Speaker
Biography:

Weiru Wang has completed his PhD in Biophysics from Cornell University and Post-doctoral studies from University of California, Berkeley. He is currently a Senior Scientist and a Group Leader in the Structural Biology Department at Genentech, a member of the Roche Group. His research focuses on understanding of molecular basis of protein-drug interactions using biophysical methods, primarily macromolecular crystallography.

Abstract:

Crenezumab is a fully humanized immunoglobulin isotype G4 (IgG4) monoclonal antibody that binds to monomeric as well as aggregated Aβ forms (oligomers, fibers and plaques). Notably, crenezumab binds with higher affinity to Aβ oligomers over monomers and in vitro studies have demonstrated crenezumab’s ability to block Aβ aggregation and promote Aβ disaggregation. To understand the structural basis for this activity and crenezumab’s broad binding profile, we determined the crystal structure of crenezumab in complex with Aβ. The structure reveals a sequential epitope and the conformational requirements for epitope recognition, which include a subtle but critical element that is likely the basis for crenezumab’s versatile binding profile. We find interactions consistent with high affinity for multiple forms of Aβ, particularly oligomers. Crenezumab also sequesters the hydrophobic core of Aβ and breaks an essential salt-bridge characteristic of the β-hairpin conformation, eliminating features characteristic of the basic organization in Aβ oligomers and fibrils, and explains crenezumab’s inhibition of aggregation and promotion of disaggregation. These insights highlight crenezumab’s unique mechanism of action, particularly regarding Aβ oligomers and provide a strong rationale for the evaluation of crenezumab as a potential treatment for patients with Alzheimer’s disease.

Speaker
Biography:

Yasuo Norikane has received his PhD in 2001 from University of Tsukuba, Japan, for investigating the photochemistry of intramolecularly hydrogen-bonded molecules, under the supervision of Professor Tatsuo Arai. From 2001-2003, he carried out his Postdoctoral research on novel crystal structure and photo-isomerization in macrocyclic azobenzenes with Dr. Nobuyuki Tamaoki at AIST. After serving as a second Post-doctorate with Professor M. Reza Ghadiri at the Scripps Research Institute, he began his carrier as a Researcher in AIST. He was awarded a Commendation for Science and Technology by The Minister of Education, Culture, Sports, Science and Technology, Japan. He is currently a Group Leader at Electronics and Photonics Research Institute and an Associate Professor at Department of Chemistry, University of Tsukuba. His research focuses on organic photochemistry especially in design and synthesis of photofunctional materials using photochromic compounds such as azobenzene.

Abstract:

Creating self-propelled motion in nano- to macroscopic sized objects has been of interest to scientists. Physical or chemical energy has been used to obtain motion of liquid droplets or solid objects in various media. Using light as an energy source, photochromic molecules have been utilized to induce various mechanical motions of objects. In many cases, the mechanical motions involve the photochemical reactions of azobenzene molecules, which exhibit photoisomerization between trans and cis isomers. So far, various type of motion has been reported; however, photo-induced translational motion of crystals on solid surfaces is unknown. Recently, we have been interested in photochemically-induced phase transitions between solid and liquid phases in photochromic organic compounds such as macrocyclic or rod-shaped azobenzene derivatives. Materials’ showing the phase transition has been of interest because of its interesting properties such as photocontrollable adhesives, photoresists and motion on water surface. Here, we report the novel crawling motion of crystals of simple azobenzenes such as azobenzene and 3,3'- dimethylazobenzene on a glass surface. The motion is directional and continuous when irradiated simultaneously with two different wavelengths (365 and 465 nm). Our method is simple as crystals move on a bare glass surface using a light-emitting diodes or Hg lamp as light sources in a fixed position. The direction of the motion can be controlled by the position of the light sources and the crystals can even climb vertical surfaces. The motion proceeds without changing the crystal orientation, despite the large deformation of the crystal shape. There is a no need for any special treatment such as chemical modification, spatial gradient or application of ratchet potential of the solid surface. It is presumed that the motion is driven by crystallization and melting at the front and rear edges of the crystal, respectively, via photochemical conversion between the crystal and liquid phases induced by the trans-cis isomerization of azobenzenes

Changyong Park

Carnegie Institution for Science, USA

Title: Hydration and ion adsorption at yttria-stabilized zirconia (YSZ) – water interface

Time : 15:00-15:20

Speaker
Biography:

Changyong Park is a Beamline Scientist at HPCAT, Sector 16 of Advanced Photon Source located at Argonne National Laboratory. He developed the Resonant Anomalous X-ray Reflectivity technique for probing element-specific ion-adsorption profiles at mineral and aqueous solution interfaces (Park and Fenter, 2007). Combined with the high spatial resolution feature in the High-Resolution X-ray Reflectivity, this technique allows probing both specifically and non-specifically bound ion species at mineral surfaces, thus identifying the sterically resolved adsorbed species, i.e., inner-sphere adsorbed species vs. outer-sphere species.

Abstract:

Understanding hydration and exchange processes at metal-oxide-water interface is important to metal surface passivation. The fine structural information is crucial to describe the molecular characteristics; therefore, an ability to directly probe the hydrated surface structure in-situ is highly desired. Zirconia has numerous applications including gas sensors, solid oxide fuel cell electrolytes, bio-medical materials, substrate for film-growth, etc. and plays a key role in protecting zirconium alloys in highly corrosive environments like nuclear power plants, pressurized water reactors. Its degradation is known primarily caused by the surface interaction with water. Here we report the detailed interfacial hydration structures at 8 mol% yttria-stabilized zirconia (8YSZ) surfaces in (100), (110), and (111) orientation, respectively, with high-resolution X-ray reflectivity (HRXR). We could identify common features of these hydrated surfaces as well as differences intrinsic from the surface chemistry. All three surfaces terminate with significant numbers of point defect presumable caused by the metal depletion and the intrinsic oxygen vacancies. Apparently, water molecules fill those vacancies, forming highly ordered and layered structure near the surfaces. Above the termination planes, two additional adsorbed layers are consisting of the surface hydration structures. The first adsorbed layers likely include metal species as indicated by the promoted electron densities, whereas the second layers seem to be pure water. We also studied the effect of zinc adsorption on the interfacial hydration structures, which show obvious changes in the hydration structure at (100) and (111) surfaces, but minor changes at (110) surface. We determined the detailed element specific adsorption profile of Zn2+ ions at YSZ (110) and (111)-water interfaces with resonant anomalous X-ray reflectivity (RAXR) measurements. With the adsorbed zinc species, the (100) and (110) surfaces maintain the original features in the pristine hydration layers qualitatively, while the interfacial hydration at (111) surface is completely altered by the zinc adsorption.

Speaker
Biography:

Stephan Rosenkranz is a Senior Physicist in Materials Science Division at Argonne National Laboratory, USA. He has completed his Ph.D. in Physics in 1996 at ETH Zurich. His Diploma in experimental physics in 1992 at ETH Zurich. His research interest is on Structure and dynamics of strongly correlated systems, in particular the role of phase competition in generating complex phenomena. Investigation of long-range order and excitations and short-range correlations and fluctuations due to the presence of ground states with competing order.

Abstract:

Correlated defects are responsible for the functional properties of many materials that underpin energy-related technologies. Single-crystal diffuse scattering using x-rays or neutrons offers a powerful probe of such short-range order in crystalline lattices, but its use has been limited by the experimental challenge of collecting data over a sufficiently large volume of reciprocal space and the theoretical challenge of modeling the results. However, instrumental and computational advances at both x-ray and neutron sources now allow the efficient measurement and rapid transformation of reciprocal space data into three-dimensional pair distribution functions, providing model-independent images of nanoscale disorder in real space. We discuss how these recent developments of efficient methods of measuring single crystal diffuse scattering provide new insights into cation disorder in electrode materials. Large volumes of measured diffuse scattering in reciprocal space are transformed into 3D difference pair distribution functions (3D-ΔPDF) that image defect-defect correlations in real space, allowing a model-independent view of short-range order. We demonstrate this with data on β-NaxV2O5 with x=0.2 and 0.4 over the temperature range 100K to 500K. The sodium intercalants partially occupy sites on two-rung ladders penetrating the framework of vanadium oxide pyramids and octahedra, with no long-range order at room temperature and above. However, at x=0.4, the length scale of sodium-sodium correlations increases significantly below 200K with the emergence of forbidden Bragg peaks below an order-disorder transition. The 3D-ΔPDF directly reveal that the sodium ions occupy alternate sites on each ladder rung, with a zig-zag configuration that is in phase with neighboring ladders. The growth in the length scale of sodium-sodium correlations with decreasing temperature is clearly seen in real space images that allow a quantitative determination of the interionic interactions that impede ionic mobility.

Break: Networking & Refreshment Break 15:40-16:00 @ Athens

Kensuke Kobayashi

High Energy Accelerator Research Organization (KEK), Japan

Title: Structural response to pressure in 1111-type iron-based superconductor LaFeAsO1-xHx

Time : 16:00-16:20

Speaker
Biography:

Kensuke Kobayashi has received his doctor’s degree in science from Osaka City University in 2009. Since April 2010, he has been a researcher at Condensed Matter Research Center (CMRC), Institute of Material Structure Science, KEK. At present, he is a Project Assistant Professor (MEXT Element Strategy Initiative) and worked on experimental studies of the structural and electrical properties of materials by means of synchrotron X-ray diffraction under external fields, such as pressure, electric field and low temperature

Abstract:

Iron-based superconductor (iron pnictides) and cuprates are most well-known types of superconductor with critical temperature (Tc) higher than 50 K. In iron-based superconductors, the relation between the maximum Tc and structural parameters of FePn4 (Pn = pnictide) has been proposed as follows: the highest Tc is achieved when the Pn-Fe-Pn bond angle (αPn-Fe-Pn) approaches 109.5° as in a regular tetrahedron of FePn4 or when the Pn height from Fe plane (hPn) ~ 1.38 Å. The application of pressure is a direct and clean way to modify the local geometry of FePn4 without the degradation of the crystal in comparison to the chemical substitution; hence, the detailed crystal structure under pressure warrants further investigation. A systematic study of the crystal structure of a layered iron oxypnictide LaFeAsO1-xHx, with a unique phase diagram of two superconducting phases and two parent phases, as a function of pressure was performed using synchrotron X-ray diffraction. We established that the αAs-Fe-As widens on application of pressure due to the interspace between the layers being nearly infilled by the large La and As atoms. This behavior implies that the FeAs4 coordination deviates from the regular tetrahedron in our systems, which breaks a widely accepted structural guide albeit the increase of Tc from 18 K at ambient pressure to 52 K at 6 GPa for x = 0.2. In the phase diagram, the second parent phase at x ~ 0.5 is suppressed by low-pressure at ~1.5 GPa in contrast to the first parent phase at x ~ 0, which remains robust to pressure. We suggest that the spin/orbital fluctuation from the second parent phase gives rise to the high-Tc under pressure. The pressure responses of the FeAs4 modification, the parent phases, and their correlation are previously unexplained peculiarities in 1111-type iron-based superconductors.

Awalendra Kumar Thakur

Indian Institute of Technology Patna, India

Title: Role of crystal structure stability for energy storage applications

Time : 16:20-16:40

Speaker
Biography:

A. K. Thakur is currently working at the Department of Physics at the Indian Institute of Technology Patna, India as Associate Professor. His research area is experimental condensed matter physics and applied physics with focus on wide variety of materials including ceramics and polymer composites for device applications including sensors, EMI shielding and renewable energy. His current interest lies in development of new generation of novel functional materials for clean and green energy alternatives

Abstract:

Materials research for energy storage applications has drawn considerable attention in recent years owing to growing alertness on saving earth from impending dangers of pollution, implementation of stricter emission norms across the globe and emerging emphasis on development of clean/green energy alternatives. To meet this challenge, chain of efforts aimed at bringing a paradigm shift in energy research is underway. Potential candidates are solar photovoltaics, fuel cells and storage devices. Further, the best considered and commercially available alternative is solar photovoltaics. However, it cannot act itself as a standalone energy solution. It requires storage devices as backup for providing energy when source of solar energy recedes into background during night. The most sought-after storage devices are high energy density rechargeable batteries, supercapacitors and a hybrid of the two. All energy storage devices are based on conversion of stored chemical energy into electrical energy. Energy storage devices, being multi component system, primarily comprise a separator compartment sandwiched between two electrodes (anode & cathode). Energy storage capability is determined by its crystallographic structure. Crystallographic structure & phase, structural stability and strain bearing capability of these components play a crucial role in determining their suitability as a storage device component. Such applications require a single phase layered crystallographic structure with attributes such as; (a) availability of guest sites for intercalation-deintercalation of cations during charge-discharge cycles, (b) layered tunnel type structure along all the planes in a 3-D geometry, (c) presence of crystalline structure with a flexible framework, (d) sustainability of volume expansion with capability of withstanding lattice strain, (e) phase stability etc.. In the present work, we report a review of the crystallographic features of some important material structures used in energy storage applications. State of-the-art developments in the area covering recent emphasis on development of new generation of materials with structural suitability for high energy density applications is proposed to be discussed with summary of the ongoing work in our laboratory at IIT Patna.

Speaker
Biography:

Xing-Zhong Li has his expertise in transmission electron microscopy on materials and nanoscience. He started the works on computer programs for electron diffraction simulation and crystallographic analysis a decade ago. He works in Nebraska Center for Materials and Nanoscience, University of Nebraska

Abstract:

Landyne software suite is the 2.0 version of the previous JECP—a Java Electron Crystallography Project. The software suite currently includes eight stand-alone computer programs. Each of them was designed for one topic of application in electron diffraction simulation, crystallographic analysis or experimental data processing and quantification. Figure 1 shows the classification of the computer programs in the Landyne suite according to their functionality. The computer programs have been grouped into a suite to increase the total usefulness and a launcher has been developed for the users to conveniently access all of the computer programs. The purpose of this software suite is twofold: i) as research tools to analyze experimental results, ii) as teaching tools to show students the principles of electron diffraction and crystallography. The software suite was programmed using Java SE Development Kit 8. It has been successfully tested on Microsoft Windows 7, 8 and 10 with a Java virtual machine, i.e. Java 2 Runtime Environment (J2RE). The executable codes, user manuals and a set of crystal structural data are available. The design and functions of the computer programs will be elucidated in this presentation. Three examples are listed here: SAED is used for simulation and analysis of electron diffraction patterns including twins and two phases with a fixed orientation and the search for the zone axes of experimental patterns; SPICA is for the calculation of stereograms and related applications; LAUNCE is for lattice reconstruction and unit cell determination of unknown crystal phases in TEM experiments. The application of the Landyne suite in our recent research works will be also discussed.

Speaker
Biography:

Yoshinori Ohmasa studied physics at Kyoto University and received PhD from Kyoto University. His doctoral thesis is about the phase transitions and the structure of chalcogen mixed crystals under high pressure. He worked at Kyoto University from 1996 to 2008, and moved to Hiroshima Institute of Technology, and then to Kansai University. His research interest covers the field of structurally disordered materials, such as liquid, glass, alloys and disordered crystals. Especially, he has been studying phenomena related to liquid surface, such as wetting and capillary waves.

Abstract:

Highly oriented pyrolytic graphite (HOPG) is a form of carbon, which is composed of many crystallites arranged uniaxially. The c-axes of the crystallites are aligned along a single direction, while the a- and b-axes are distributed randomly in the plane perpendicular to the c-axis. HOPG is used in a wide range of scientific and technological areas, for example as a monochromator of X-ray and neutron beams.

We measured small-angle X-ray scattering from HOPG and observed radial streak patterns. When the sample is rotated, the number and the direction of the streaks change. The streaks are divided into two categories: (i) A pair of streaks which forms X-shaped pattern. The angle between the two streaks changes with sample rotation, and they appear and disappear in pairs. (ii) A single streak which appears only in a narrow range of the sample rotation angle. Examples of the streak patterns of the type (i) and (ii) are shown in Fig.1 and 2, respectively.

We found that the appearance of the streaks is explained by double Bragg scattering. They appear in the small-angle region because the first scattered X-ray is scattered back to the small-angle region. The streaks of the type (i) is caused by the successive Bragg reflections hkl and hkl with , and (ii) is by 00l and 00l.The dependence of the streak directions on the sample rotation angle is in good agreement with theoretical prediction.

The double Bragg scattering observed in the present work is an obstacle to obtaining the ‘true’ small-angle scattering. On the other hand, the intensity profile of the double Bragg scattering pattern itself is interesting because it contains various pieces of information on the sample structure. For example, the width and length of the streaks are related to the distribution of crystallites

Serife Yalcin

Harran University, Turkey

Title: How does crystallography affect material properties?

Time : 17:20-17:40

Speaker
Biography:

Serife Yalcin has completed her PhD from Erciyes University and Postdoctoral studies from Caen University. She has published more than 40 papers in reputed journals and has been serving as an Editorial Board Member of repute.

Abstract:

Statement of the Problem: Developments in science and technology have required the production of new materials and design. Knowing the properties of the materials used to obtain them are helpful to design and manufacture of materials that we need. Crystallography studies have been very important for developing of materials because this studies deal with internal structure, in particular the symmetry of crystal. The majority of the solid materials are composed of crystals. This explains how much important crystallography is in material. The purpose of this study is to determine suitable materials for material science need.

Methodology & Results: Crystallography is the science of structure used for characterization of materials and to determine some physical properties with microstructure and texture analyses. It includes the general features of structure and deals with the mapping of all kinds of systems as geometrical representations. The same material with different crystallographic parameter has different properties. It is hardly possible to develop materials science without crystallographic techniques. As a sample, we will focus on structure of calcium carbonate. Calcium carbonate is one of the most abundant and cheap material found in nature. It can be found in three forms: Calcite, aragonite and vaterite. XRD pattern of aragonite, calcite and vaterite shows difference as seen in Figure-1. These patterns show difference depending on crystal structure. When Scanning Electron Microscopy (SEM) image investigate of different forms of calcium carbonate, it has been observed difference among picture. Calcite structure shows square structure while aragonite and vaterite structure show rod and flower type structure, respectively.

Conclusion & Significance: The results have showed difference depending on the form of calcium carbonate. Young modulus has been obtained 76, 89-193 Pa for calcite and aragonite, respectively. Preparation of materials that is needs of human must be in coordination with crystallography