Anisotropic magnetoresistance in low-doped La0.79Ca0.21MnO3 crystals

Anisotropic magnetoresistance (AMR) in La0.79Ca0.21MnO3 single crystals has been investigated. In contrast with previous studies, in our experiments AMR increases with decreasing temperature, reaches the maximum below TC and decreases with further temperature decrease. Variations of MR while rotating the sample around the [110] crystalline direction may be associated with uniaxial magnetocrystalline anisotropy. The unusual enhancement of AMR below TC is ascribed to changes in the magnetic domain structure revealed by magneto-optical techniques.