title: Giant facet-dependent spin-orbit torque and spin Hall conductivity in the triangular antiferromagnet IrMn3.
abstract: There has been considerable interest in spin-orbit torques for the purpose of manipulating the magnetization of ferromagnetic elements for spintronic technologies. Spin-orbit torques are derived from spin currents created from charge currents in materials with significant spin-orbit coupling that propagate into an adjacent ferromagnetic material. A key challenge is to identify materials that exhibit large spin Hall angles, that is, efficient charge-to-spin current conversion. Using spin torque ferromagnetic resonance, we report the observation of a giant spin Hall angle [Formula: see text] of up to ~0.35 in (001)-oriented single-crystalline antiferromagnetic IrMn3thin films, coupled to ferromagnetic permalloy layers, and a [Formula: see text] that is about three times smaller in (111)-oriented films. For (001)-oriented samples, we show that the magnitude of [Formula: see text] can be significantly changed by manipulating the populations of various antiferromagnetic domains through perpendicular field annealing. We identify two distinct mechanisms that contribute to [Formula: see text]: the first mechanism, which is facet-independent, arises from conventional bulk spin-dependent scattering within the IrMn3layer, and the second intrinsic mechanism is derived from the unconventional antiferromagnetic structure of IrMn3. Using ab initio calculations, we show that the triangular magnetic structure of IrMn3gives rise to a substantial intrinsic spin Hall conductivity that is much larger for the (001) than for the (111) orientation, consistent with our experimental findings.
authors.affiliation: IBM Research-Almaden, San Jose, CA 95120, USA.; Department of Materials Science Engineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Zhang
authors.affiliation: IBM Research-Almaden, San Jose, CA 95120, USA.; International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Wei
authors.identifier: 0000-0002-1757-4479
authors.initials: W
authors.lastname: Han
authors.affiliation: IBM Research-Almaden, San Jose, CA 95120, USA.
authors.forename: See-Hun
authors.initials: SH
authors.lastname: Yang
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany.
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany.
authors.forename: Yang
authors.identifier: 0000-0003-4630-5056
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany.
authors.forename: Binghai
authors.identifier: 0000-0003-2164-5839
authors.initials: B
authors.lastname: Yan
authors.affiliation: IBM Research-Almaden, San Jose, CA 95120, USA.; Max Planck Institute for Microstructure Physics, Halle (Saale) D-06120, Germany.
authors.forename: Stuart S P
authors.initials: SS
authors.lastname: Parkin
mesh_terms: D004553:Electric Conductivity; D060526:Magnetic Fields; D008280:Magnetics; D059346:Magnets / Q000737:chemistry*; D009915:Orbit; D010825:Physics; D013499:Surface Properties; D019415:Torque
keywords: IrMn3; Spintronics; antiferromagnet; spin Hall angle; spin Hall conductivity; spin orbit torque; spin orbitronics; triangular antiferromagnet