A New Property of Ferromagnetic‐Antiferromagnetic Coupling

Abstract

Abstract Three systems exhibiting ferromagnetic‐antiferromagnetic coupling, CoCoO, NiFeNiFeMn, NiFeCr 2 O 3 , are studied using uniaxial thin films. A new property of such systems is found, i.e., a concentration of the hysteresis loops as a function of the number of cycles traced ( n ). This contraction follows a 1/ \documentclass{article}\pagestyle{empty}\begin{document}$\sqrt n $\end{document} n law for the first 50 cycles and is related to the rotational hysteresis. This phenomenon is attributed to fluctuations in the ferromagnetic‐antiferromagnetic coupling, which modify the magnetic interactions between differently coupled regions with each reversal.