Current-induced magnetization switching in Pt/Co/Ta with interfacial decoration by insertion of Cr to enhance perpendicular magnetic anisotropy and spin-orbit torques
Abstract
Perpendicular magnetic anisotropy (PMA) and spin-orbit torques (SOTs) are studied in a perpendicularly magnetized ultrathin Co film sandwiched between heavy metal Pt and Ta with an interfacial decoration performed by inserting a 3d transition metal Cr layer with a thickness of 2 nm between the Co and Ta. A significant enhancement of the perpendicular anisotropy field (H\text{an}0 = 11{,}560 Oe) is established and estimated by measuring the extraordinary Hall resistance due to the Cr interfacial decoration. The improved antidamping-like field of ∼18.59 × 10-6 Oe/(A·cm-2) reveals a large effective spin Hall angle θ \text{SH}\text{eff} of Pt/Co/Cr/Ta ∼0.41, which is caused by employing the dissimilar metals, Pt and Ta, with spin Hall angles of opposite sign and an additional interfacial spin-orbit coupling effect related to the Cr insertion. Thus, SOT-induced magnetization switching was achieved under a relatively small critical current density of the order of 106 A/cm2 owing to the improved SOTs in the Pt/Co/Cr/Ta system. Our results indicate that the PMA and SOTs in Pt/Co/Cr/Ta structures can be enhanced via a Cr interfacial decoration.
- Publication:
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Applied Physics Express
- Pub Date:
- January 2018
- DOI:
- 10.7567/APEX.11.013001
- arXiv:
- arXiv:1708.09174
- Bibcode:
- 2018APExp..11a3001C
- Keywords:
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- Physics - Applied Physics
- E-Print:
- 14 pages, 6 figures