Effective indirect multi-site spin–spin interactions in the s–d(f) model

• Published in: Journal of magnetism and magnetic materials Vol. 440; pp. 57 - 59
• Main Authors: Komarov, K.K., Dzebisashvili, D.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.10.2017; Elsevier BV
• Subjects: Dynamic models; Electrons; Green's functions; Infinite series; Magnetism; Mult i-site spin–spin interactions; Spin dynamics; Spin-orbit interactions; s–d(f) exchange model; s–d(f) exchange model; Mult i-site spin–spin interactions
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2016.12.075

Using the diagram technique for Matsubara Green's functions it is shown that the dynamics of the localized spin subsystem in the s–d(f) model can be described in terms of an effective spin model with multi-site spin–spin interactions. An exact representation of the action for the effective purely spin model is derived as an infinite series in powers of s–d(f) exchange interaction J. The indirect interactions of the 2nd, 3rd and 4th order are discussed. •Localized spins in the s-d-model are described within effective purely spin model with multi-site spin-spin interactions.•The action for corresponding purely spin model is derived as an infinite series in powers of s-d(f) exchange interaction.•The indirect interactions of the 2nd, 3rd and 4th order are discussed.