Anisotropy Effects on Magnetization and Heat Capacity in Antiferromagnets

Desalgne Tefera
Physics Department, Debre Birhan University, P.O. Box 445, Debre Birhan, Ethiopia

Chernet Amente
Physics Department, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.

Abstract

 This study theoretically examines the influence of uniaxial anisotropy on the thermodynamic proper ties of two-sublattice antiferromagnets, focusing on magnetization and magnon heat capacity (MHC). The analysis employs the Heisenberg model with a uniaxial anisotropy field, treated using quantum f ield theory and the double-time temperature-dependent Green’s function under the random phase approximation. In the low-temperature and long-wavelength limits, dispersion relations of uniax ial symmetric AFM lattices are applied to evaluate the temperature dependence of magnetization and heat capacity. The results reveal that both magnetization and MHC exhibit strong sensitivity to anisotropy: increasing anisotropy enhances the deviation in magnetization and suppresses the peak value of the heat capacity. These findings contribute to a deeper understanding of the role of anisotropy in the thermal behavior and stability of antiferromagnetic materials, which is relevant for their potential applications in spintronic technologies.

Keywords: Anisotropic field; dispersion; spin wave; spin-excitation; temperature variable, linear dispersion, Sinusoidal disperstion

Author Biographies

Desalgne Tefera, Physics Department, Debre Birhan University, P.O. Box 445, Debre Birhan, Ethiopia

Chernet Amente, Physics Department, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.