Change of longitudinal spin Seebeck voltage with annealing in Y3Fe5O12 films formed by densely packed nanocrystals

Abstract The changes of longitudinal spin Seebeck (LSSE) voltage with annealing temperature Ta and time in Y3Fe5O12 (YIG) films formed by densely packed nanocrystals on a Si substrate have been investigate. The value of thermoelectric performance (TP) decreases monotonically with increasing Ta from 1073 K to 1273 K, and it decreases by up to 24% (64%) in the YIG films with Pt = 5 nm (10 nm). The decreased TP is also observed with increasing annealing time. These results indicate that the microstructural changes in the YIG films by annealing temperature and time are caused the decreased TP, which are corresponded with a reduced coherence of the magnons in the YIG films.