Effect of the texture and the applied magnetic field on the reversible temperature coefficient of αJ of permanent magnets

The reversible temperature coefficient of the polarization, α_J, is calculated and measured in dependence of the applied magnetic field for textured magnets based on Nd₂Fe ₁₄B, Sm₂Co₁₇ and SmCo₅. For moderately aligned magnets, the reversible loss at a typical operating field strength of H=-5 kA/cm is up to 30% larger than for H =0. This behaviour is well described by the results of the calculations, which are based on the Stoner-Wohlfahrt theory. The variations of α_J with respect to the applied magnetic field result from the difference between the temperature dependence of the anisotropy field, H_A, and the saturation polarization, J_s