Exceptionally High, Strongly Temperature Dependent, Spin Hall Conductivity of SrRuO₃

Abstract

Spin-orbit torques (SOT) in thin film heterostructures originate from strong spin-orbit interactions (SOI) that, in the bulk, generate a spin current as the result of extrinsic spindependent, skew or/and side-jump, scattering, or in the intrinsic case due to Berry curvature in the conduction band. While most SOT studies have focused on materials with heavy metal components, the oxide perovskite SrRuO3 has been predicted to have a pronounced Berry curvature. Through quantification of its spin current by the SOT exerted on an adjacent Co ferromagnetic layer, we determine that SrRuO3 has a strongly temperature (T) dependent spin Hall conductivity which becomes particularly high at lowT, e.g. 5 1 1 / 2 3 10 m SH e  −−    at 60 K. Below the SrRuO3 ferromagnetic transition, nonstandard SOT components develop associated with the magnetic characteristics of the oxide, but these do not dominate as with spin currents from a conventional ferromagnet. Our results establish a new approach for the study of SOI in epitaxial conducting oxide heterostructures and confirm SrRuO3 as a promising candidate material for achieving new and enhanced spintronics functionalities.

Magnetic asymmetry induced anomalous spin-orbit torque in IrMn

“…11). In FM systems, the unusual sz has been attributed to the spin-orbit precession [12], the spin rotation symmetry [14], the AMR effect and the anomalous Hall effect [15,16,38]. These processes require the net magnetization of FM and sz is very sensitive to interfaces.…”

Modulation of Spin–Orbit Torque from SrRuO3 by Epitaxial‐Strain‐Induced Octahedral Rotation

“…In recent studies, sizable SOT has been observed experimentally in both SrIrO 3 and SrRuO 3 . [ 36–38 ] Variations of the SOT efficiency with the thickness of SrIrO 3 and SrRuO 3 were attributed to the thickness‐dependent octahedral rotation. [ 36,38 ] However, the relation between the octahedral rotation and SOT is still blurred due to limited evidences.…”

Novel Spin–Orbit Torque Generation at Room Temperature in an All‐Oxide Epitaxial La0.7Sr0.3MnO3/SrIrO3 System

“…In particular, 5d transition metal oxides (TMO), with strong SOC and electron–electron correlation, give rise to intriguing fundamental physics, ranging from nontrivial quantum phases [ 28–30 ] to magnetic anisotropy manipulation [ 31 ] and intrinsic charge‐spin interconversion. [ 32–35 ] However, despite this rich physics, in the few room temperature studies on charge‐spin interconversion in 5d TMOs, the adjacent FM metal has typically been a non‐epitaxial metal, such as SrIrO 3 (SIO)/Permalloy (Py), [ 32,33 ] SIO/Co 1− x Tb x , [ 34 ] and SrRuO 3 /Co. [ 35 ] The resulting SOT efficiencies, ξ || ≤ 1, [ 32–35 ] are comparable to their HM/FM counterparts.…”

“…[ 32–35 ] However, despite this rich physics, in the few room temperature studies on charge‐spin interconversion in 5d TMOs, the adjacent FM metal has typically been a non‐epitaxial metal, such as SrIrO 3 (SIO)/Permalloy (Py), [ 32,33 ] SIO/Co 1− x Tb x , [ 34 ] and SrRuO 3 /Co. [ 35 ] The resulting SOT efficiencies, ξ || ≤ 1, [ 32–35 ] are comparable to their HM/FM counterparts. With this as the background, our hypothesis was that creating atomically perfect ferromagnet and SOC metal layers, coupled through chemically abrupt epitaxial interfaces, can lead to emergent electronic phenomena at the interfaces, [ 31 ] as well as the opportunity to obtain more efficient charge‐to‐spin conversion.…”