Spin transfer torque on magnetic insulators

¹ Department of Physics, Beijing Normal University - Beijing 100875, China
² Institute for Materials Research, Tohoku University - Sendai 980-8577, Japan
³ Delft University of Technology, Kavli Institute of NanoScience - 2628 CJ Delft, The Netherlands, EU

^a kexia@bnu.edu.cn

Received: 13 June 2011
Accepted: 17 August 2011

Abstract

Recent experimental and theoretical studies focus on spin-mediated heat currents at interfaces between normal metals and magnetic insulators. We resolve conflicting estimates for the order of magnitude of the spin transfer torque by first-principles calculations. The spin mixing conductance G^↑↓ of the interface between silver and the insulating ferrimagnet Yttrium Iron Garnet (YIG) is dominated by its real part and of the order of 10¹⁴ Ω⁻¹ m⁻², i.e. close to the value for intermetallic interface, which can be explained by a local spin model.