Spin reorientation effect on magnetization: application to Nd2Fe14B

Abstract Spin reorientation is a phenomenon observed frequently in magnetic materials and is responsible for changes in magnetization as a function of temperature. In this study an analytical model is described which accounts for such changes in magnetization. Three different magnetization vs. temperature measurements are described which confirm the occurence of spin reorientation and indicate the exact temperature at which it occurs (application to Nd 2 Fe 14 B intermetallic compound). The analytical solution of the model enables one to determine the K 1 / K 2 ratio of the first- ( K 1 ) and second-order ( K 2 ) anisotropy constants as a function of temperature. Also, this model clearly demonstrates the effect of crystal orientation (angle between the c -axis and the applied magnetic field) on the magnetization vs. temperature behavior; one can take advantage of this in order to achieve a maximum or a minimum effect. The effect of the presence of the third-order ( K 3 ) anisotropy constant is also discussed.