Tuning the exchange bias by using Cr interfacial dusting layers

Le résumé fourni par la source

Exchange biased Fe/CoO bilayers with a Cr spacer layer between Fe and CoO layers have been studied using magnetometry. The Cr ``dusting'' layer thickness was varied between 0 and $10\text{ }\text{\AA{}}$. Independent of the growth method we find that the coercive field ${H}_{c}$ drops much faster than the exchange bias field ${H}_{\text{eb}}$ as a function of increasing Cr thickness. We attribute this effect to a rapid decoupling between the Fe and CoO layers with increasing Cr thickness. First, Cr decorates the grain boundaries on top of the CoO layer and screens the pinning centers for ferromagnetic domain walls. On further increasing the nominal Cr thickness the surface of the CoO grains is covered, which leads to a weakening of the exchange interactions at the interface and thus of ${H}_{\text{eb}}$. Furthermore, we show that the effect of the Cr-dusting layer on the system is insensitive upon the variation of the CoO-layer stoichiometry, whereas ${H}_{\text{eb}}$ and ${H}_{c}$ of the Cr-free CoO/Fe system vary significantly.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.