• Bhattacharya, Anand
• Chapai, Ramakanta
• Arava, Hanu
• Park, Hyowon
• Welp, Ulrich
• Jiang, J. S.
• Li, Yue
• Liu, Yuzi
• Pearson, John
• Du, Qianheng

Abstract

We use co-sputtering to directly synthesize thin films of the A15 phase intermetallic compound Ta3Sb, which has been predicted to have a giant spin Hall conductivity. We identify a large window of Ta:Sb flux ratio that stabilizes single-phase A15 Ta3Sb. Composition analyses of these films show a Ta:Sb atomic ratio of 4:1, which is consistent with the known Ta-Sb phase diagram. The spin Hall conductivity of thin film Ta3Sb is -3400+/-400 (hbar/2e) S/cm and the spin-orbit torque efficiency is -0.6+/-0.1 at 20 K, as determined from harmonic Hall measurements of Ta3Sb/permalloy bilayer structures. These giant values make Ta3Sb a promising material for efficient charge-to-spin conversion in spintronic applications. Large field-like spin-orbit effective fields that are independent of the ferromagnetic layer thickness have also been measured in the Ta3Sb/permalloy bilayers. We attribute the field-like spin-orbit effective field to the Rashba effect at the interface.

Topics

• impedance spectroscopy
• compound
• phase
• thin film
• intermetallic
• phase diagram