Unusual transition from negative to positive magnetoresistance in n-n heterojunctions composed of La0.9Hf0.1MnO3 and Nb-doped SrTiO3L. Wang, Z. P. Wu and J. GaoEPL, 95 6 (2011) 67003DOI: https://doi.org/10.1209/0295-5075/95/67003