Anisotropic transport properties in the phase-separated La_0.67Ca_0.33MnO₃/NdGaO₃ (001) films

The anisotropic transport property was investigated in a phase separation La_0.67Ca_0.33MnO₃ (LCMO) film grown on (001)-oriented NdGaO₃ (NGO) substrate. It was found that the resistivity along the b-axis is much higher than that along the a-axis. Two resistivity peaks were observed in the temperature dependent measurement along the b-axis, one located at 91 K and the other centered at 165 K. Moreover, we also studied the response of the resistivities along the two axes to various electric currents, magnetic fields, and light illuminations. The resistivities along the two axes are sensitive to the magnetic field. However, the electric current and light illumination can influence the resistivity along the b-axis obviously, but have little effect on the resistivity along the a-axis. Based on these results, we believe that an anisotropic-strain-controlled MnO₆ octahedra shear-mode deformation may provide a mechanism of conduction filaments paths along the a-axis, which leads to the anisotropic transport property.