Minor hysteresis loop phenomena in particulate recording media

Abstract

In this article measurements of minor hysteresis loops in substituted BaFe powder systems with different particle concentrations have been made. The area of minor loop is observed to decrease with decreasing particle concentration. In addition, the variation of magnetization with time along the upper and lower sections of the minor loop have also been measured and show an inflection point at particular field points. The field at which the rate of magnetization changes sign is believed to be equal to a positive (magnetizing) local interaction field, i.e., the negative applied field is balanced by a local positive field. These results suggest that minor hysteresis loops originate from interactions driving irreversible changes of magnetization during the cycling process of the magnetic field. Hence the opening of minor loops in these systems is governed by the ratio of interaction to anisotropy fields.