In this report we discuss the nature of minor hysteresis in ferromagnets. In particular we have examined the formation of minor loops in which the magnetisation in the second quadrant is at a higher positive value, as the magnitude of H is increasing in a negative sense, than it is during a reverse sweep back to zero field. This behaviour produces the well known elliptical minor loops, or the 'eye effect'. We have examined in some detail changes in magnetisation on these minor loops and we infer that these are changes in the irreversible component of magnetisation. Such changes are anomalous as the sample is maintained in a negative field at all times. We have also observed time dependent changes in magnetisation in which M increases in a positive sense in a negative field. Analysis of this effect shows that it alone is insufficient to account for the eye effect. We discuss the origins of the eye effect in terms of interaction effects in materials and show that this phenomenon can occur in dipolar and exchange coupled materials and may provide a technique for probing local interaction effects.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics