A possible model for the positive magnetoresistance in manganite-based all-perovskite oxide films p-n junctionD. J. Wang, Y. W. Xie, C. M. Xiong, B. G. Shen and J. R. Sun
State Key Laboratory for Magnetism, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences Beijing 100080, PRC
received 12 November 2005; accepted in final form 8 December 2005
published online 4 January 2006
The electrical transport properties of a heterostructure (LPCM)/ doped (STON) junction were studied. The LPCM film is metallic and ferromagnetic below the Curie temperature (Tc) with a colossal magnetoresistance (MR) effect found around Tc. The junction shows good rectifying property. Negative MR was observed by two-terminal current-voltage (I-V) curves measurement. However, the sign of the MR depends on temperature and the current applied with the four-probe technique. Positive MR may be attributed to the competition between LPCM MR and the junction MR. A simple model is proposed to interpret the related origin.
75.47.Gk - Colossal magnetoresistance.
73.50.-h - Electronic transport phenomena in thin films.
73.40.Lq - Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions.
© EDP Sciences 2006