Mean field theory for double-perovskites

Abstract

A mean field approximation of a model for double perovskites that takes into account the coupling between itinerant electron spins and localized spins is developed. As in previously reported theoretical results, and contrary to experimental observation, the critical temperature is suppressed for large electron density. An effective Heisenberg model reveals the cause of this discrepancy: the competition between degenerate antiferromagnetic and ferromagnetic channels. This degeneracy can be broken by the inclusion of a Hubbard-type U term. It is therefore suggested that electron correlation effects need to be incorporated in the minimal model of double perovskites in order to explain the experimental observation of increasing ferromagnetic critical temperature with increasing electron doping.

8 pages, including 4 figures

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Cited by in corpus (10)

• Theory of Half-metallic Ferrimagnetism in Double Perovskites
• Theory of Half-Metallic Double Perovskites I: Double Exchange Mechanism
• Origin of Magnetism and trend in $T_c$ in Cr-based double perovskites: Interplay of two driving mechanisms
• Evidence of Kinetic Energy Driven Antiferromagnetism in Double Perovskites : A First-principles Study
• A Magnetic Model for the Ordered Double Perovskites
• Magnetism in Sr${}_2$CrMoO${}_6$: A combined abinitio and model study
• Spin-orbital locked magnetic excitations in a half-metallic double perovskite Ba2FeReO6
• Theory of metallic double perovskites with spin orbit coupling and strong correlations; application to ferrimagnetic Ba2FeReO6
• Understanding ferromagnetism in Cr-based 3d-5d double perovskites
• Magnetic Skyrmionic Polarons