Spin–charge conversion in transition metal oxides

The interaction between spin and charge degrees of freedom offers a powerful tool to manipulate magnetization in memories by the current induced spin–orbit torque. This novel phenomenon, conventionally existing in semiconductors and metallic systems, has recently been observed in transition metal oxides, exhibiting a surprising large spin-Hall angle. In this Perspective, we will review recent research progress in the spin–charge conversion in transition metal oxides, the remaining challenges, and new opportunities. We will first briefly summarize recent progress in the spin–charge conversion in representative transition metal oxides, including SrIrO3, SrRuO3, and IrO2, along with other materials predicted by calculations. Next, we will survey the possible candidate materials in the family of transition metal oxides. Recent advances in the growth of SrIrO3 films will be reviewed along with the implications on the study of the spin-Hall effect. We will also discuss other promising candidates that could serve as the spin source, including films of pyrochlore and delafossite oxides as well as oxide heterostructures.