Disordered local moment
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The disordered local moment (DLM) picture is a method, in theoretical physics, for describing the electronic structure of a magnetic material at finite temperature, where a probability distribution of sizes and orientations of atomic magnetic moments must be considered.[1][2][3][4] Its was pioneered, by Balázs Győrffy, Julie Staunton, Malcolm Stocks, and co-workers.
The underlying assumption of the DLM picture is similar to the Born-Oppenheimer approximation for the separation of solution of the ionic and electronic problems in a material. In the disordered local moment picture, it is assumed that 'local' magnetic moments which form around atoms are sufficiently long-lived that the electronic problem can be solved for an assumed, fixed distribution of magnetic moments[5]. Many such distributions can then be averaged over, appropriately weighted by their probabilities, and a description of the paramagnetic state obtained.
The picture is typically based on density functional theory (DFT) calculations of the electronic structure of materials. Most frequently, DLM calculations employ either the Korringa–Kohn–Rostoker (KKR)[6] (sometimes referred to as multiple scattering theory) or linearised muffin-tin orbital (LMTO) formulations of DFT, where the coherent potential approximation (CPA) can be used to average over multiple sizes and orientations of magnetic moment. However, the picture has also been applied in the context of supercells containing appropriate distributions of magnetic moment orientations.[7]
References
[edit]- ^ Pindor, A J; Staunton, J; Stocks, G M; Winter, H (1983). "Disordered local moment state of magnetic transition metals: a self-consistent KKR CPA calculation". Journal of Physics F: Metal Physics. 13 (5): 979–989. doi:10.1088/0305-4608/13/5/012. ISSN 0305-4608.
- ^ Staunton, J.; Gyorffy, B. L.; Pindor, A. J.; Stocks, G. M.; Winter, H. (1984). "The "disordered local moment" picture of itinerant magnetism at finite temperatures". Journal of Magnetism and Magnetic Materials. 45 (1): 15–22. doi:10.1016/0304-8853(84)90367-6. ISSN 0304-8853.
- ^ Staunton, J; Gyorffy, B L; Pindor, A J; Stocks, G M; Winter, H (1985). "Electronic structure of metallic ferromagnets above the Curie temperature". Journal of Physics F: Metal Physics. 15 (6): 1387–1404. doi:10.1088/0305-4608/15/6/019. ISSN 0305-4608.
- ^ Gyorffy, B L; Pindor, A J; Staunton, J; Stocks, G M; Winter, H (1985). "A first-principles theory of ferromagnetic phase transitions in metals". Journal of Physics F: Metal Physics. 15 (6): 1337–1386. doi:10.1088/0305-4608/15/6/018. ISSN 0305-4608.
- ^ Mendive Tapia, Eduardo (2020), Mendive Tapia, Eduardo (ed.), "Disordered Local Moment Theory and Fast Electronic Responses", Ab initio Theory of Magnetic Ordering: Electronic Origin of Pair- and Multi-Spin Interactions, Cham: Springer International Publishing, pp. 29–54, doi:10.1007/978-3-030-37238-5_3, ISBN 978-3-030-37238-5, retrieved 2024-09-25
- ^ Faulkner, J. S.; Stocks, G. Malcolm; Wang, Yang (2018-12-01). Multiple Scattering Theory: Electronic structure of solids. IOP Publishing. doi:10.1088/2053-2563/aae7d8. ISBN 978-0-7503-1490-9.
- ^ Mendive-Tapia, Eduardo; Neugebauer, Jörg; Hickel, Tilmann (2022-02-17). "Ab initio calculation of the magnetic Gibbs free energy of materials using magnetically constrained supercells". Physical Review B. 105 (6): 064425. doi:10.1103/PhysRevB.105.064425.