Europhys. Lett.
Volume 73, Number 3, February 2006
Page(s) 401 - 407
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 04 January 2006
Europhys. Lett., 73 (3), pp. 401-407 (2006)
DOI: 10.1209/epl/i2005-10411-9

A possible model for the positive magnetoresistance in manganite-based all-perovskite oxide films p-n junction

D. 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 $\chem{La_{0.32}Pr_{0.35}Ca_{0.33}MnO_{3}}$ (LPCM)/$\chem{Nb}$ doped $\chem{SrTiO_{3}}$ (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.

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