Prof. dr Helena Zapolsky
Université de Rouen, Saint-Etienne du Rouvray, France
"Multiscale modelling of phase transitions"

2. 10. 2013


The phase field method has recently emerged as a powerful computational approach to modelling and predicting mesoscale morphological and microstructure evolution in materials. It describes a microstructure using two field variables: concentration (a conserved variable) and order parameter (nonconserved variable). The temporal and spatial evolution of these field variables is governed by the Cahn-Hilliard non-linear diffusion equation and the Allen-Cahn relaxation equation. At present stage the phase field method is able to predict the evolution of arbitrary morphologies and complex microstructures. However, some important phenomena like defects formation, grain boundaries motion or reconstructive phase transitions require atomic scale study. Recently an approach coined atomic density function (ADF) modelling has been developed to incorporate atomic-level crystalline structures into standard continuum theory for pure and binary systems. The ADF model describes the diffusive, large-time-scale dynamics of the atomic density field ?, which is spatially periodic on atomic length scales. In this talk the application of phase field and ADF models for various material processes including solidification, solid-state structural phase transformations, coarsening and microstructure evolution will discussed.

Prof. dr Koki Takanashi
IEEE Distinguished Lecturer, Institute for Materials Research (IMR), Tohoku University, Japan
"Advanced spintronic materials for generation and control of spin current"

16. 10. 2013


"Spin current", i.e., the flow of spin angular momentum, in magnetic nanostructures has emerged as a fascinating physical concept during the recent development of spintronics. In magnetic nanostructures, magnetism correlates strongly with electronic transport and also other physical properties, leading to the mutual control of magnetic, transport, and other physical properties. Spin current is the most basic concept relevant to the mutual control, and efficient generation and precise control of spin current in magnetic nanostructures are key technologies for the further development of spintronics. There are two kinds of spin current: one is accompanied by an electric current, and the other is not. Spin current without an electric current is called pure spin current, which is actually generated by several experimental methods such as non-local spin injection, spin Hall effect, spin pumping, spin Seebeck effect, and so on. For recent years spin current has been extensively investigated, and particularly the understanding of pure spin current has dramatically developed.
In this lecture the concept, historical background, and recent progress in research of spin current will be reviewed, and then some topics on advanced materials for the generation and control of spin current will be introduced, with a focus on magnetic ordered alloys: half-metallic Heusler alloys as a highly efficient spin injector/detector and L10-ordered alloys with high magnetic anisotropy as a perpendicularly polarized spin injector/detector.

Prof. dr hab. Rafał Abdank-Kozubski
M. Smoluchowski Institute of Physics Jagiellonian University
"Atomistic simulations of diffusion and diffusion-controlled transformations in intermetallic phases"

23. 10. 2013


Decomposition and precipitation in alloys, as well as the self- and interdiffusion processes in intermetallics have been modeled at the atomistic scale using hybrid Monte Carlo - Molecular Statics (MC/MS) algorithms with many-body semi-empirical potentials. Three particular results are reported: (i) The discontinuous transformation from "in-plane" to "off-plane" L10 variant in [001]-oriented FePt nano-layers simulated with Analytic Bond-Order Potentials (ABOP) dedicated to FePt; (ii) The configuration of the eutectic mixture of Ag and Cu precipitates modelled in bulk and nano-layered Ag-40at.%Cu by simulations implemented with many-body potential derived for Ag-Cu within the Second-Moment-Approximation and (iii) The Ising-model-based MC simulations of atomic ordering and self-diffusion in the triple-defect B2 binary system.

Dr Wojciech Tabiś
Solid State Physics Department, Faculty of Physics and Computer Science, AGH UST
School of Physics and Astronomy, University of Minnesota
"Synchrotron radiation studies of the high-temperature superconductors Hg1201"

30. 10. 2013


The high-temperature superconductors have been of a great interest to the scientific community for nearly 30 years. The complex phase diagram of these fascinating materials contains many competing phases that should be widely explored in order to understand the origin of the superconducting properties. HgBa2CuO­4+d (Hg1201) is considered as a model superconductor because it contains a relatively low number of atoms per elementary unit cell and features the highest critical temperature (Tc = 97 K) among all the cuprates with only one CuO2 plane per elementary unit cell. The application of various X-ray scattering and absorption techniques will be discussed in the context of an interplay between the electronic and crystallographic structure of Hg1201 aimed to explore key aspects of its rich phase diagram. As the charge concentration controls many physical properties of the supercodductors, a particular attention will be paid to the oxygen dopant ordering in the reservoir layer and the associated charge doping mechanism.