Anomalous shape of magnetic loops in the Rayleigh region

Abstract

According to its congruency property, the Preisach model demands an equivalent shape of magnetic minor loops, the so-called Rayleigh loops. We measured these loops with an inductive setup and noticed a different anomalous shape of Rayleigh loops which depends on the magnetic history. Special materials (particularly recording media) show a concave-convex shape in contrast to the normal biconvex shape. This anomalous shape can be explained by combining the Preisach model with the Stoner–Wohlfarth model. It follows from this explanation that the degree of the anomaly depends on the material, especially in how far it fulfills the conditions of the Stoner–Wohlfarth model. The experiments show the effect that is expected according to the material. In this way the measurement of the anomalous Rayleigh loops can be used as a new method to test the Stoner–Wohlfarth properties of a material. This is more effective than using the Henkel plot [G. Bertotti and V. Basso, J. Appl. Phys. 73, 5827 (1993)].