Exchange bias of polycrystalline Heusler alloy thin films

Abstract

It is accepted that Heusler alloys have a great deal of potential for applications in spintronic devices due to their high magnetic moment and spin polarisation at the Fermi level. However for this potential to be realised it is necessary to create structures where one ferromagnetic layer is pinned allowing the other to rotate thus creating aGMRor TMR effect.One possible technique to pin one ferromagnetic layer is to exchange bias it in a similar manner to that used for CoFe ferromagnetic layers in devices such as read heads. In this work we review progress which has been made in attempting to exchange bias such films. It is found that it is possible to achieve a significant level of exchange bias using carefully controlled growth and annealing processes. A significant exchange bias can be achieved using the temperature limits normally associated with silicon device electronics. Hence one potential obstacle to the application of Heusler alloys has been successfully addressed.