Preisach parameter identification for systems with negative mean field interactions

Summary form only given. A simplified algorithm has be developed to determine the parameters of the generalized Preisach model. The algorithm is based on evaluating the Preisach model parameters in the operative plane considering the real applied field to be given by the sum of the external applied field and the internal field. One of the major problems of parameter identification in Preisach models is the separation of the mean field and the statistical interactions effects. This problem has been solved by using the properties of the Integral Generalised /spl Delta/M plot. When applied to data sets for a number of samples of flexible magnetic recording media, reasonable parameter values are produced, although the mean field parameter (/spl alpha/) may be positive or negative. The authors show a good fit of simulations to the experimental data for the major hysteresis loop (MHL), dc demagnetization curve (DCD) and the isothermal remanent magnetization curve starting from the dc demagnetized state of the system (IRM/sub dc/). The experimental data was generated for a Hi8 video tape and the simulations have been made using the generalized Preisach model with the parameters obtained using the algorithm.. In this case the value of the mean field parameter was /spl alpha/=-450 Oe. In most cases, simulations of acicular particulate systems generate a positive mean field, but for certain geometric configurations of the particles, the mean field may be negative. There is some experimental evidence in support of this from studies of isolated and interacting particles where negative mean fields have been found for metal particle systems. In this paper we will describe the experimental results and simulations of the Preisach parameters for a range of samples that show both positive and negative values for /spl alpha/ and conclusions will be drawn about these two groups.