Characteristics of spin-thermoelectric generators enhanced by incorporating liquid phase epitaxial Bi-substituted YIG films as a ferrimagnetic insulator

Liquid phase epitaxial (LPE) Bi-substituted YIG films exhibit a large growth-induced magnetic anisotropy (GIMA) perpendicular to the film surface. The GIMA depends on the melt composition and supercooling in the LPE growth. Our film shows a large Ku value of 0.1 × 104 J/m3 even at a Bi content, x, of 0. We assume that GIMA enhances the spin-orbital coupling (SOC) in the local d-electron spins of Fe3+, and that the SOC-enhanced thermal energy transfer from the phonon system to the spin system increases spin currents in spin-thermoelectric (STE) generation. We discuss the characteristics of STE generators on the basis of data obtained from ferromagnetic resonance measurements.