Preisach analysis of La0.67Pb0.33MnO3

The perovskite La0.67Pb0.33MnO3 with a Curie temperature T-C = 360K has been characterized by measuring the zero-field-cooled(ZFC) and field-cooled (FC) moments over a wide range of temperature 2K < T < 380K in the applied field of h(a) = 3978.87A/m, and also the major hysteresis loop over the field range \h(a)\ less than or equal to 160kA/m at T = 10K. The data have been analysed within the framework of a generalized version of the Preisach model of the hysteresis, which combines thermal fluctuations with the growth of the free energy barriers below T-C. Numerical simulations replicate all of the principal structural systematics of the data, including the hystersis loop and the magnetization and the susceptibility under the ZFC/FC conditions. Finally, the details of the spectrum of Barkhausen instabilities are discussed in this material.