Anomalous photovoltaic effect in Las_0.8Sr_0.2MnO₃ films grown on SrTiO₃(001) substrates by laser molecular beam epitaxy

¹ Department of Mathematics and Physics, China University of Petroleum, Beijing 102249, P.R. China
² Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, P.R. China
³ International Center for Materials Physics, Chinese Academy of Sciences, Shenyang 110016, P.R. China
⁴ Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, P.R. China

Corresponding author: ainiphoto@163.com

Received: 24 September 2005
Revised: 24 March 2006
Accepted: 19 May 2006
Published online: 13 July 2006

Abstract

Transient laser-induced anomalous photovoltaic effect has been studied in La_0.8Sr_0.2MnO₃ films grown on the SrTiO₃ (001) substrates by laser molecular beam epitaxy. It is demonstrated that the signal polarity is reversed when the films are irradiated through the substrate rather than at the air/film interface. The microstructures in these films 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 V/K, where S_ab and S_c are the ab-plane and c-axis Seebeck coefficients.