Tuning the remanent spin structure of exchange coupled magnetic films

We have investigated the remanent coupling between a soft-magnetic and a hard-magnetic film separated by a nonmagnetic spacer layer. It turned out that the remanent coupling angle of the soft-magnetic layer relative to the hard-magnetic layer can be adjusted by temporarily applied external fields. The underlying mechanism is the competition between the exchange field and the soft layer coercive field. This could be applied in modern magnetic recording techniques like MRAMs to realize multiple or even continuous states per memory cell, thus constituting a re-emergence of analogue recording technology with the potential of much higher information density