The spin polarization of palladium on magneto-electric Cr₂O₃

Authors

Takashi Komesu, University of Nebraska - LincolnFollow
Will Echtenkamp,, University of Nebraska-Lincoln
Christian H. Binek, University of Nebraska-LincolnFollow
Peter A. Dowben, University of Nebraska-LincolnFollow

Date of this Version

4-12-2023

Citation

J. Phys.: Condens. Matter 35 (2023) 275801 (8pp) https://doi.org/10.1088/1361-648X/acc710

Comments

Used by permission.

Abstract

While induced spin polarization of a palladium (Pd) overlayer on antiferromagnetic and magneto-electric Cr₂O₃(0001) is possible because of the boundary polarization at the Cr₂O₃(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 Cr₂O₃(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 Cr₂O₃(0001) at 310 K, i.e. above the Néel temperature of bulk Cr₂O₃. While Cr₂O₃(0001) has surface moments that tend to align along the surface normal, for Pd on Cr₂O₃, the spin polarization contains an in-plane component. Strain in the Pd adlayer on Cr₂O₃(0001) appears correlated to the spin polarization measured in spin polarized inverse photoemission spectroscopy. Further evidence for magnetization of Pd on Cr₂O₃ is provided by measurement of the exchange bias fields in Cr₂O₃/Pd(buffer)/[Co/Pd]_n 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.