Backward diode behavior in oxygen-excessive manganite-titanate p-n junction Y. W. Xie, J. R. Sun, D. F. Guo, B. G. Shen and X. Y. Zhang EPL, 87 5 (2009) 57006 Published online: 22 September 2009 DOI: 10.1209/0295-5075/87/57006