Magnetic cluster expansion model for random and ordered magnetic face-centered cubic Fe-Ni-Cr alloys

Journal Article · Thu Jul 28 04:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4958981· OSTI ID:22597776

Nguyen-Manh, D.; Dudarev, S. L. ^[1]; Wróbel, J. S. ^[1]; Ganchenkova, M. G. ^[2]

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1. CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)
2. Materials Science Department, National Research Nuclear University MEPhI, 31 Kashirskoe sh., 115409 Moscow (Russian Federation)

A Magnetic Cluster Expansion model for ternary face-centered cubic Fe-Ni-Cr alloys has been developed, using DFT data spanning binary and ternary alloy configurations. Using this Magnetic Cluster Expansion model Hamiltonian, we perform Monte Carlo simulations and explore magnetic structures of alloys over the entire range of compositions, considering both random and ordered alloy structures. In random alloys, the removal of magnetic collinearity constraint reduces the total magnetic moment but does not affect the predicted range of compositions where the alloys adopt low-temperature ferromagnetic configurations. During alloying of ordered fcc Fe-Ni compounds with Cr, chromium atoms tend to replace nickel rather than iron atoms. Replacement of Ni by Cr in ordered alloys with high iron content increases the Curie temperature of the alloys. This can be explained by strong antiferromagnetic Fe-Cr coupling, similar to that found in bcc Fe-Cr solutions, where the Curie temperature increase, predicted by simulations as a function of Cr concentration, is confirmed by experimental observations. In random alloys, both magnetization and the Curie temperature decrease abruptly with increasing chromium content, in agreement with experiment.

• OSTI ID: 22597776
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 4 Vol. 120; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANTIFERROMAGNETISM
ATOMS
BCC LATTICES
CHROMIUM ALLOYS
CLUSTER EXPANSION
COMPUTERIZED SIMULATION
CONCENTRATION RATIO
CONFIGURATION
CURIE POINT
FCC LATTICES
HAMILTONIANS
IRON ALLOYS
LIMITING VALUES
MAGNETIC MOMENTS
MONTE CARLO METHOD
NICKEL
NICKEL ALLOYS
RANDOMNESS
TEMPERATURE RANGE 0065-0273 K
TERNARY ALLOY SYSTEMS