We have studied the temperature dependence of low-field magnetoresistance and current-voltage characteristics of a low-angle bi-crystal grain boundary junction in perovskite manganite La_{2/3}Sr_{1/3}MnO_3 thin film. By gradually trimming the junction we have been able to reveal the non-linear behavior of the latter. With the use of the relation M_{GB} \propto M_{bulk}\sqrt{MR^*} we have extracted the grain boundary magnetization. Further, we demonstrate that the built-in potential barrier of the grain boundary can be modelled by V_{bi}\propto M_{bulk}^2 - M_{GB}^2. Thus our model connects the magnetoresistance with the potential barrier at the grain boundary region. The results indicate that the band-bending at the grain boundary interface has a magnetic origin.
@article{arxiv.cond-mat/0112184,
title = {A model for spin-polarized transport in perovskite manganite bi-crystal grain boundaries},
author = {R. Gunnarsson and A. Kadigrobov and Z. Ivanov},
journal= {arXiv preprint arXiv:cond-mat/0112184},
year = {2009}
}