Interactions characterisation in particulate magnetic recording media. Experiments and Preisach model

New ways of experimental characterisation of interactions in particulate re cording media have been investigated, Experimental procedures to obtain Del ta M-like curves (generalised Delta M plots) which are sensitive to both st atistical and mean-field interactions between the ferromagnetic particles i n the system are analysed, The generalised Delta M plots allow Delta M-like plots to be produced from any reproducible initial remanent state. Another set of experimental curves sensitive to interactions ape AC demagnetisatio n and anhysteretic remanent magnetisation. Measurements were performed on s amples in the form of flexible particulate magnetic films (gamma-Fe2O3 VHS tape and Ba-ferrite dispersed powder films, oriented and not oriented) show ing both positive and negative mean-field interaction effects. The experime ntal results were compared with the simulations made with a scalar generali sed moving preisach model. There was good agreement between the theory and experiment for DC remanent magnetisation measurements but the fit was poore r for AC measurements. (C) 1999 Elsevier Science B.V. All rights reserved.