The Temperature Dependence of the Magnetisation and Anisotropy of Ultrathin Ferromagnetic Films
The problem of the thermal stability of the magnetisation has attracted renewed interest since recent investigations of ultrathin epitaxial films establish the existence of long range magnetic order in plane [1,2]. We have used spin-wave theory  which can be expected to provide an adequate description of the excitation spectrum where the magnetisation is close to saturation, i.e., at temperatures significantly smaller than the Curie temperature. We take into account the effects of the dipole interaction, exchange interaction, ~Zeeman enegy and the magnetocrystalline anisotropy without restriction to the uniaxial case. The exchange gap for these spin waves is determined by a combination of the various anisotropy constants. We show that the temperature dependence of the magnetisation deviation is given in terms of the energy gap alone for a two dimensional magnetic film, and also the small in-plane anisotropies cannot be neglected for monolayer films.
KAPLAN, Bengü (1997) "The Temperature Dependence of the Magnetisation and Anisotropy of Ultrathin Ferromagnetic Films," Turkish Journal of Physics: Vol. 21: No. 1, Article 41. Available at: https://journals.tubitak.gov.tr/physics/vol21/iss1/41