Anomalous photovoltaic effect in La0.8Sr0.2MnO3. lms grown on SrTiO3 (001) substrates by laser molecular beam epitaxy

摘要

Transient laser-induced anomalous photovoltaic effect has been studied in La0.8Sr0.2MnO3. lms grown on the SrTiO3 (001) substrates by laser molecular beam epitaxy. It is demonstrated that the signal polarity is reversed when the. lms are irradiated through the substrate rather than at the air/.lm interface. The microstructures in these. lms are clarified in terms of the oriented microdomains with their (101) plane parallel to the substrate surface, suggesting off-diagonal Seebeck effect plays an important role for our observation. From the results, we obtain the anisotropy of the thermoelectric power. Delta S = S-ab - S-c = 0.3 mu V/K, where S-ab and S-c are the ab-plane and c-axis Seebeck coefficients.