Resistivity and Hall effect at high temperatures in La0.67Ca0.33MnO3

The resistivity tensors of La0.67Ca0.33MnO3 films were investigated at temperatures from the Curie temperature up to 600 K in magnetic fields up to 20 T. The diagonal transport is described by hopping of a small spin polaron cluster of 4 ions to nearest-neighbor spins. A spin-dependent activation energy and a mean field approximation for the magnetization of clustered polaron spins and unclustered Mn ion spins allowed the description of ?(B,T) with a minimum of free parameters. The electron-like low field Hall coefficient showed a thermally activated behavior with an activation energy higher than that extracted from diagonal data. © 1999 American Institute of Physics