Theoretical characterization of the temperature-dependent saturation magnetization of magnetic metallic materials

Abstract

Abstract Based on the force–heat equivalence energy density principle, a theoretical model for magnetic metallic materials is developed, which characterizes the temperature-dependent magnetic anisotropy energy by considering the equivalent relationship between magnetic anisotropy energy and heat energy; then the relationship between the magnetic anisotropy constant and saturation magnetization is considered. Finally, we formulate a temperature-dependent model for saturation magnetization, revealing the inherent relationship between temperature and saturation magnetization. Our model predicts the saturation magnetization for nine different magnetic metallic materials at different temperatures, exhibiting satisfactory agreement with experimental data. Additionally, the experimental data used as reference points are at or near room temperature. Compared to other phenomenological theoretical models, this model is considerably more accessible than the data required at 0 K. The index included in our model is set to a constant value, which is equal to 10/3 for materials other than Fe, Co, and Ni. For transition metals (Fe, Co, and Ni in this paper), the index is 6 in the range of 0 K to 0.65T cr (T cr is the critical temperature), and 3 in the range of 0.65T cr to T cr, unlike other models where the adjustable parameters vary according to each material. In addition, our model provides a new way to design and evaluate magnetic metallic materials with superior magnetic properties over a wide range of temperatures.