Exchange biasing and interlayer coupling in Co/Pt/Co/CoO multilayers with perpendicular anisotropy

- Magnetization reversal behaviors are related to thickness of Pt spacer and CoO layer.
- Onset of exchange biasing starts at lower temperature with thinner CoO layer.
- These ascribe to competition between exchange biasing and interlayer coupling.

Investigations have been performed on exchange biasing and interlayer coupling in the Co/Pt/Co/CoO multilayers with perpendicular anisotropy. We have observed the asymmetry of the magnetization reversal of the top Co layer in contact with CoO layer and the shifting EHE loops of the bottom Co layer, which could be ascribed to the competition between the interfacial exchange biasing of the top Co layer and interlayer coupling between Co layers across the Pt layer. Due to other oxide phases observed in CoO layer, non-stoichiometric structure of CoO lowers the blocking temperature for the exchange biasing systems. The blocking temperature also depends on the CoO thickness and we observed lower blocking temperature for the thinner CoO layer.