Exchange coupled CoPd/TbCo magneto-optic storage films

Films of CoPd with weak perpendicular anisotropy have been shown to exchange couple to square loop TbCo films on both the Tb and Co sides of compensation. The exchange is sensitive to reactive impurities at the interface and is broken under conditions that produce as little as one monolayer of paramagnetic compound. Even when the coupling at the interface is strong, it is shown that only a limited thickness of the CoPd layer is spin oriented perpendicular. It is noted that the CoPd system has some potential for applications in that it has a higher Faraday rotation than TbCo at short wavelengths of interest for higher-density storage systems