Unified decoupling scheme for exchange and anisotropy contributions and temperature-dependent spectral properties of anisotropic spin systems

Abstract

We compute the temperature-dependent spin-wave spectrum and the magnetization for a spin system using the unified decoupling procedure for the high-order Green's functions for the exchange coupling and anisotropy, both in the classical and quantum case. Our approach allows us to establish a clear crossover between quantum-mechanical and classical methods by developing the classical analog of the quantum Green's function technique. The results are compared with the classical spectral density method and numerical modeling based on the stochastic Landau-Lifshitz equation and the Monte Carlo technique. As far as the critical temperature is concerned, there is a full agreement between the classical Green's functions technique and the classical spectral density method. However, the former method turns out to be more straightforward and more convenient than the latter because it avoids any \emph{a priori} assumptions about the system's spectral density. The temperature-dependent exchange stiffness as a function of magnetization is investigated within different approaches.

References in corpus (5)

• Many-body Green's function theory of Heisenberg films
• Theory of field induced spin reorientation transition in thin Heisenberg films
• Anisotropy effects on the magnetic excitations of a ferromagnetic monolayer below and above the Curie temperature
• Spin-wave theory for finite classical magnets and superparamagnetic relation
• Callen-like method for the classical Heisenberg ferromagnet

Cited by in corpus (12)

• Quantitative simulation of temperature dependent magnetization dynamics and equilibrium properties of elemental ferromagnets
• Thermal spin dynamics of yttrium iron garnet
• Controlling the Polarity of the Transient Ferromagnetic-Like State in Ferrimagnets
• Quantum Landau-Lifshitz-Bloch equation and its comparison with the classical case
• Temperature scaling of the Dzyaloshinsky-Moriya interaction in the spin wave spectrum
• A review of modelling in ferrimagnetic spintronics
• Temperature scaling of two-ion anisotropy in pure and mixed anisotropy systems
• Pulse-noise approach for classical spin systems
• Magnon-Magnon Interactions in O(3) Ferromagnets and Equations of Motion for Spin Operators
• Uniform and non-uniform thermal switching of magnetic particles
• Temperature dependence of spin-model parameters in antiferromagnets
• Surface-induced reduction of the switching field in nanomagnets