Approximation and Validation of Integral Coefficients in Correlation Magnetodynamics Based on Atomistic Spin Dynamics
Abstract:
The equations of correlation magnetodynamics (CMD) are derived from the atomistic model of a classical Heisenberg ferromagnet, taking into account correlations between nearest neighbors, and describe the magnet in the approximation of a continuous medium. In this paper, analytical approximations of the integral coefficients of CMD are constructed based on the results of ”atom-in-atom” modeling. The obtained approximations are tested for primitive, body-centered and face-centered cubic crystal lattices on a large number of model problems in a wide temperature range. A new algorithm for calculating the entropy of a magnet based on one- and two-particle distribution functions is substantiated. It is shown that the traditional Landau–Lifshitz–Bloch (LLB) equation is a special case of CMD, which allows to refine the calculation of the exchange energy for LLB. The constructed approximation of the integral coefficients of CMD makes CMD suitable for solving a wide range of engineering problems.
