The dependence of the remanence curves of particulate media on the initial magnetic configuration

The isothermal remanence curve of a particulate recording medium is shown experimentally to depend upon the method used to achieve the demagnetized state. As-prepared powder samples exhibit larger initial remanence slopes than after AC field demagnetization. This can be interpreted in terms of a higher degree of correlation introduced by the particle-particle interactions during the demagnetization process. Theoretical calculations using a Monte Carlo model give good qualitative agreement with experimental data