New approach to experimental investigation of coercivity temperature dependence

It is shown that, if some conditions are fulfilled, it is possible to use Preisach\´s model for the investigation of the distribution function which has a character and temperature dependence similar to the distribution function of local critical fields. At the critical fields an irreversible movement of the Bloch walls appears. This distribution function is not affected by the internal interaction fields. Using its first moment the first approximation of the macroscopic coercive force Hcmay be obtained. As an example, the temperature dependence of the function , which was obtained for a square-loop MnMg-ferrite in the temperature interval from -194°C up to 200°C is presented. The results are compared with the directly measured macroscopic coercive force temperature dependence.