RESUMO
We report on temperature dependent measurements of the longitudinal spin Seebeck effect (LSSE) in the mixed valent manganite La_{0.7}Ca_{0.3}MnO_{3}. By disentangling the contribution arising due to the anisotropic Nernst effect, we observe that in the low temperature regime, the LSSE exhibits a T^{0.5} dependence, which matches well with that predicted by the magnon-driven spin current model. Across the double exchange driven paramagnetic-ferromagnetic transition, the LSSE exponent is significantly higher than the magnetization one, and also depends on the thickness of the spin-to-charge conversion layer. These observations highlight the importance of individually ascertaining the temperature evolution of different mechanisms-especially the spin mixing conductance-which contribute to the measured spin Seebeck signal.