About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Physical Review B - CMMP
Paper
Coercivity mechanisms in positive exchange-biased Co films and Co/Pt multilayers
Abstract
We describe magnetization measurements on a simple model system that mimics the behavior of positive exchange bias. The system consists of an antiferromagnetic CoO layer exchange coupled to antiferromagnetically coupled Co/Ru/Co or [Co/Pt]N/Co/Ru/[Co/Pt]M multilayer films with in-plane and out-of-plane anisotropy, respectively. In both cases, the two ferromagnetic layers were chosen to have different thickness with the thinner layer coupled to the CoO layer. When cooled below the blocking temperature of the CoO layer the thinner ferromagnetic layer is pinned and the low-field response is governed by the reversal of the thicker ferromagnetic layer with an effective exchange bias that is mediated via the Ru interlayer. For all the films studied we observe a transition in the effective bias from negative to positive with increasing cooling field. However, when varying the cooling field we find three distinct coercivity behaviors during the transition from positive to negative bias that depends on the anisotropy and microstructure of the ferromagnetic layers.