Spin Current at the 5d–3d Interface of Epitaxial Oxide Films (Brief Review)

Experimental studies of the electrophysical and magnetic properties of a heterostructure of complex SrIrO₃/La_0.7Sr_0.3MnO₃ oxides, where a spin current is observed under ferromagnetic resonance conditions, have been reviewed. thin films of 5d strontium iridate SrIrO₃ with a strong spin–orbit coupling and 3d strontium manganite La_0.7Sr_0.3MnO₃ have been grown epitaxially on a (110) NdGaO₃ single-crystal substrate by magnetron sputtering at a high substrate temperature of 7000–8000°C in a mixture of argon and oxygen gases at a total pressure of 0.3 mbar. The spin mixing conductance of the interface, which has real (Reg^↑↓) and imaginary (Img^↑↓) parts, has been determined from the frequency dependences (in the range of 2–20 GHz) of the linewidth and the resonant field of the ferromagnetic resonance of the SrIrO₃/La_0.7Sr_0.3MnO₃ heterostructure. The spin Hall angle θ_SH, which characterizes the efficiency of the conversion of the spin current into an electric current in the presence of the inverse spin Hall effect, has been calculated from the data on the spin magnetoresistance of the SrIrO₃/La_0.7Sr_0.3MnO₃ heterostructure. The spin Hall angle θ_SH of the SrIrO₃/La_0.7Sr_0.3MnO₃ heterostructure turns out to be significantly larger (by a factor of almost 40) than that for the Pt/La_0.7Sr_0.3MnO₃ heterostructure.