All-oxide ferromagnetic resonance and spin pumping with SrIrO3

SrIrO3 is a semimetallic complex oxide of interest for spintronic applications due to the large spin-orbit coupling arising from iridium. It has unusual charge transport properties derived from a complex multiband electronic structure, with electron and hole pockets both contributing to conductivity. We report ferromagnetic resonance of La0.7Sr0.3MnO3 and SrIrO3 epitaxial bilayer films on (LaAlO3)0.3(Sr2AlTaO6)0.7 substrates. Anomalous trends in the out-of-plane magnetic anisotropy and Landé g factor suggest that orbital magnetism is modified by proximity of SrIrO3 at low temperatures, likely contributing to large (∼fivefold) enhancements in Gilbert damping. However, enhanced Gilbert damping due to spin pumping is also apparent in the temperature range 250–300 K. The effective spin-mixing conductance is evaluated to be G↑↓eff∼0.5×1014Ω−1m−2, and the spin scattering length scale of SrIrO3 is of the order of ∼1 nm. Our work demonstrates the delicate interplay of pure spin current with interfacially mediated spin-orbit effects in a complex oxide heterostructure, exploiting temperature as a control parameter, and should be of interest for both spin pumping and understanding the electronic structure of thin film iridates.