Unusual transition from negative to positive magnetoresistance in n-n heterojunctions composed of La_0.9Hf_0.1MnO₃ and Nb-doped SrTiO₃

Department of Physics, the University of Hong Kong - Hong Kong, China

Received: 15 March 2011
Accepted: 2 August 2011

Abstract

We fabricated n-n heterojunctions by composing La_0.9Hf_0.1MnO₃ layers and Nb-doped SrTiO₃ crystals using pulsed-laser deposition. The formed heterojunctions demonstrated good rectifying behavior in a wide range of temperatures with or without magnetic field. It is notable that the magnetoresistance changed from negative to positive as temperature increased. The appearance of the positive magnetoresistance at higher temperatures might be understood by the occupation of minority spin carriers in the t_2g ↓ sub-band. These results might be of merits for potential application in manganite-based spintronic devices.