Affiliation:
1. Faculty of Engineering and Mathematics Bielefeld University of Applied Sciences and Arts Interaktion 1 33619 Bielefeld Germany
2. Faculty of Physics Bielefeld University Universitätsstraße 25 33615 Bielefeld Germany
3. Institute of Physics—Center for Science and Education Silesian University of Technology 44‐100 Gliwice Poland
Abstract
The exchange bias (EB) is a unidirectional anisotropy that occurs, e.g., upon field‐cooling ferromagnet/antiferromagnet systems. In many material systems, the EB field is reduced from one hysteresis loop to the next measurement. This so‐called training effect (TE) has been investigated in experiments and by means of theoretical efforts by many research groups. The reduction of the EB field as a result of subsequent magnetization reversal processes is often fitted by a power law, usually with the exception of n = 1, or with an equation based on the discretized Landau–Khalatnikov equation, as first suggested by Binek. Few other models, usually with more fitting parameters, have been proposed yet. Herein, it is shown that for large numbers of subsequent magnetization reversal processes in Co/CoO thin film samples, a modified power law or a logarithmic fit can model the TE in most cases as well as the abovementioned, commonly used models.
Subject
Condensed Matter Physics,Electronic, Optical and Magnetic Materials