Coercivity and Interfacial Spin Clusters in Exchange Bias Systems

Abstract

In this paper the current state of knowledge of the magnetic structure interfaces in exchange biased systems are briefly reviewed. A conceptual model explaining the interface in terms of spin clusters that behave in a similar manner to fine particles displaying superparamagnetism is described. To test this concept IrMn/CoFe based exchange biased polycrystalline samples of median grain diameter 7.1, 7.2 and 7.8nm were sputtered and the temperature dependence of the coupling measured. Small changes in the AF grain diameter are reflected by large volume changes in the spin clusters and consequently the temperature dependence. In particular the variation of the coercivity with temperature affects the stability of the magnetization of the spin clusters.

Recent upgrades of the neutron reflectometer D17 at ILL

“…No polarization analysis was applied. The measurement served as a reference measurement for studying the exchange bias in trilayers with different seed layers (Aley et al, 2008;Carpenter, Cramp et al, 2014;. Within symmetric trilayers, the third-order (a) A log-log plot of NR from a 95 nm thick Ni film on a 60 Â 40 mm glass substrate measured on D17 in 120 ms.…”