Measurement of the anisotropic magnetoresistance in films of La0.7Ca0.3MnO3

We present measurements of two types of anisotropic magnetoresistivity (AMR) in an epitaxial de La 0.7 Ca 0.3 MnO 3 using low magnetic fields (up to 0.6 T). First, we measure the magnetoresistivity, MR, with the applied magnetic field paralell to the film plane (in-plane) and perpendicular to the film plane (out-of-plane). With the film in the in-plane configuration, we measure the MR when the applied magnetic field is parallel and perpendicular the the injected current. The measurements have been performed at three different temperatures around the resistivity peak (T p =250 K). The observed different MR relative to the film plane can be easily explained in terms of differences in the internal demagnetization factors between the in-plane and the out-of-plane configurations. From the AMR data respecting the injected current, we observe that the amplitude of this anisotropy is around 6% at 0.5 T, independent of the temperature and slightly dependent on the magnetic field. We explain this as that the hopping of charge carriers between two adjacent polarised Mn atoms is easier when the polarisation is parallel to the charge carrier movement.