The spin polarization of palladium on magneto-electric CrO.

While induced spin polarization of a palladium (Pd) overlayer on antiferromagnetic and magneto-electric CrO(0001) is possible because of the boundary polarization at the CrO(0001), in the single domain state, the Pd thin film appears to be ferromagnetic on its own, likely as a result of strain. In the conduction band, we find the experimental evidence of ferromagnetic spin polarized in Pd thin films on a CrO(0001) single crystal, especially in the thin limit, Pd thickness of around 1-4 nm. Indeed there is significant spin polarization in 10 Å thick Pd films on CrO(0001) at 310 K, i.e. above the Néel temperature of bulk CrO. While CrO(0001) has surface moments that tend to align along the surface normal, for Pd on CrO, the spin polarization contains an in-plane component. Strain in the Pd adlayer on CrO(0001) appears correlated to the spin polarization measured in spin polarized inverse photoemission spectroscopy. Further evidence for magnetization of Pd on CrOis provided by measurement of the exchange bias fields in CrO/Pd(buffer)/[Co/Pd]exchange bias systems. The magnitude of the exchange bias field is, over a wide temperature range, virtually unaffected by the Pd thickness variation between 1 and 2 nm.