Electronic structure and effective chemical and magnetic exchange interactions in bcc Fe-Cr alloys

作     者：P. A. Korzhavyi A. V. Ruban J. Odqvist J.-O. Nilsson B. Johansson 

作者机构：Department of Materials Science and Engineering Applied Material Physics Royal Institute of Technology SE-100 44 Stockholm Sweden and R&D Centre Sandvik Materials Technology SE-811 81 Sandviken Sweden 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2009年第79卷第5期

页      面：054202-054202页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：Seventh Framework Programme  FP7  (228074) 

主　　题：chromium alloys elastic moduli electronic structure enthalpy exchange interactions (electron) Fermi surface ferromagnetic materials heat of formation Heisenberg model iron alloys Ising model lattice constants perturbation theory 

摘      要：Electronic structure calculations are employed in order to investigate the cohesive properties (lattice parameter, enthalpy of formation, and bulk modulus) of random Fe-Cr alloys as a function of composition and magnetic state, as well as to derive the chemical and magnetic exchange interactions of the constituent atoms. The calculations predict certain anomalies in the cohesive properties of ferromagnetic alloys at a concentration of about 7 at % Cr; these anomalies may be related to the changes in Fermi-surface topology that occur with composition in this alloy system. The obtained interatomic interactions are used as parameters in the configurational (Ising) and magnetic (Heisenberg) Hamiltonians for modeling finite-temperature thermodynamic properties of the alloys. We discuss the approximations and limitations of similar modeling approaches, investigate the origin of existing difficulties, and analyze possible ways of extending the theoretical models in order to capture the essential physics of interatomic interactions in the Fe-Cr or similar alloys where magnetism plays a crucial role in the phase stability.