Fitting experimental anhysteretic curves of ferromagnetic materials and investigation of the effect of temperature and tensile stress

A mean field model of the anhysteretic behaviour of magnetization, due to Jiles and Atherton, has been extended to fit experimental data for a polycrystalline iron wire. Using their approach to our experimental data, only qualitative agreement with experiment is achieved. Therefore, modelling of the effective magnetic field H-c was extended to higher order terms. Measurement of the anhysteretic curve of samples is described. An excellent fit was obtained over the whole range of magnetic field to saturation. The effect of temperature and tensile stress on parameters of the model was investigated. The temperature dependences were fit, with good accuracy, by the model described here, with one free parameter alpha, while M(s) and beta were held constant and parameter 'a' was incremented according to temperature T. The fitting of stress dependences with two free parameters alpha and beta gave qualitative agreement with experiment. The appropriateness of modelling the stress by adding the term H-sigma in the effective field H-c is confirmed.