Longitudinal spin Seebeck effect in Nd2BiFe5−xGaxO12 prepared on gadolinium gallium garnet (001) by metal organic decomposition method

Nd2BiFe5−xGaxO12 thin films with the Ga composition x = 0, 0.5, and 1.0 are prepared on (001) oriented gadolinium gallium garnet substrates by a metal organic decomposition method. Only (001) peaks are observed in x-ray diffraction patterns for all the films, suggesting that the highly oriented Nd2BiFe5−xGaxO12 thin films were formed. Increasing Ga composition, the saturation magnetization decreases, and the perpendicular easy axis is enhanced due to the decrease of the shape anisotropy. Longitudinal spin Seebeck effects (LSSEs) in Nd2BiFe5−xGaxO12 thin films with a Pt layer of 10 nm in thickness were investigated. Magnetic field dependence of the thermoelectric voltage caused by the LSSE in Nd2BiFe5−xGaxO12 films indicates the hysteresis loop with the small coercivity reflecting the magnetization curve. The decrease of LSSE voltage in Nd2BiFe5−xGaxO12 is clearly observed with the decrease of Fe composition.

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