@article{33344, keywords = {thin films, Perovskite, Heavy metals, Logic devices, Iridium compounds, Carrier concentration, Conversion efficiency, Electric insulators, Locks (fasteners), Strontium, Strontium compounds, Anticorrelation, Electronic systems, Fermi wave vectors, Interconversions, Measurement techniques, Spin conversion, Spin-logic devices, Two-materials}, author = {A.S Everhardt and M Dc and X Huang and S Sayed and T.A Gosavi and Y Tang and C.-C Lin and S Manipatruni and I.A Young and S Datta and J.-P Wang and Ramamoorthy Ramesh}, title = {Tunable charge to spin conversion in strontium iridate thin films}, abstract = {Efficient charge to spin conversion is important for low-power spin logic devices. Spin and charge interconversion is commonly performed using heavy metals and topological insulators, while the field of oxides is not yet fully explored. Strontium iridate thin films were grown, where the different crystal structures form a perfect playground to understand the key factors in obtaining high charge to spin conversion efficiency (i.e., large spin Hall angle). It was found that the semiconducting Sr2IrO4 has a spin Hall angle of ∼0.1 (depending on measurement technique), which is promising for a spin-orbit coupled electronic system and comparable to Pt. In contrast, the perovskite SrIrO3, reported to have a Dirac cone near the Fermi level, has a larger spin Hall angle of 0.3-0.4 degrees. The largest difference between the two materials is a large degree of spin-momentum locking in SrIrO3, comparable to known topological insulators. A simple semiclassical relationship is found where the spin Hall angle increases for higher degrees of spin-momentum locking and it also increases for lower Fermi wave vectors. This relationship is then able to explain the decreased spin Hall angle below 10 nm film thickness in SrIrO3, by relating it to the correspondingly higher carrier concentration (related to the higher Fermi wave vector). Breaking the commonly believed anticorrelation between resistivity and carrier concentration paves a pathway to lower power losses due to resistance while keeping large spin Hall angles. © 2019 American Physical Society.}, year = {2019}, journal = {Physical Review Materials}, volume = {3}, number = {5}, publisher = {American Physical Society}, issn = {24759953}, doi = {10.1103/PhysRevMaterials.3.051201}, note = {cited By 1}, language = {eng}, }