Longitudinal spin Seebeck effect in various garnet ferrites

Abstract

The longitudinal spin Seebeck effect (LSSE) is investigated in various garnet ferrites Y${}_{3\ensuremath{-}x}{R}_{x}$Fe${}_{5\ensuremath{-}y}{M}_{y}$O${}_{12}$ ($R=\text{Gd}$, Ca; $M=\text{Al}$, Mn, V, In, Zr) by means of the inverse spin Hall effect in Pt films. The magnitude of the LSSE voltage in the Pt/Y${}_{3\ensuremath{-}x}{R}_{x}$Fe${}_{5\ensuremath{-}y}{M}_{y}$O${}_{12}$ samples is found to be enhanced with increasing concentration of Fe in the garnet ferrites, which can be explained by a change in the spin-mixing conductance at the Pt/Y${}_{3\ensuremath{-}x}{R}_{x}$Fe${}_{5\ensuremath{-}y}{M}_{y}$O${}_{12}$ interfaces. We also investigate the dependence of the LSSE voltage on macroscopic magnetic parameters of Y${}_{3\ensuremath{-}x}{R}_{x}$Fe${}_{5\ensuremath{-}y}{M}_{y}$O${}_{12}$. The experimental results show that the LSSE voltage in the Pt/Y${}_{3\ensuremath{-}x}{R}_{x}$Fe${}_{5\ensuremath{-}y}{M}_{y}$O${}_{12}$ samples has a positive correlation with the Curie temperature and the saturation magnetization, but no clear correlation with the gyromagnetic ratio and the Gilbert damping constant of the samples.