Crossover of angular dependent magnetoresistance with the metal-insulator transition in colossal magnetoresistive manganite films

The temperature and magnetic field dependence of angular dependent magnetoresistance (AMR) along two orthogonal directions ([100] and [0 (1) over bar1]) was investigated in a charge-orbital-ordered Sm0.5Ca0.5MnO3 (SCMO) film grown on (011)-oriented SrTiO3 substrates. A dramatic decrease of AMR magnitude in both directions was observed with the appearance of magnetic-field-induced metal-insulator transition, which further led to a sign crossover in the AMR effect. The AMR crossover may give a direct evidence of the drastic modification of electronic structure or possible orbital reconstruction with the magnetic-destruction of charge/orbital ordering in SCMO films. (C) 2009 American Institute of Physics. [doi:10.1063/1.3240407]