Anisotropic magnetoresistance in colossal magnetoresistive La$_{1-x}$Sr$_{x}$MnO$_{3}$ thin films

We report on magnetic field and temperature dependent measurements of the anisotropic magnetoresistance (AMR) in epitaxial La$_{1-x}$Sr$_{x}$MnO$_{3}$ (LSMO) thin films. While in $3d$ ferromagnetic alloys increasing the magnetization, either by reducing the temperature or increasing the magnetic field, increases the AMR, in LSMO films the AMR dependence on magnetization displays non-monotonic behavior which becomes particularly pronounced in lightly doped compounds. This could imply that these samples may be electronically inhomogeneous, in which increased magnetization yields enhanced uniformity which suppresses spin-dependent scattering and hence reduces the AMR.