Temperature and angular dependence of the anisotropic magnetoresistance in epitaxial Fe films

We perform detailed temperature dependent measurements of the magnetoresistance ~MR! and its angular dependence of epitaxial Fe ~110! films. The angular dependence of the MR atH510 kOe is found to change strongly when going from T5 4.2 Kt oT5230 K. We analyze the data on the basis of Doring's equation. Second- and fourth-order angular dependent terms are found to be of equal importance, indicating strong deviations of the MR from a simple cos 2 f dependence. One of the MR components is the ordinary or Lorentz magnetoresistance, which is strong at low temperatures and becomes smaller at higher temperatures, due to the reduction of the mean free path. By subtracting the ordinary magnetoresistance from the MR data we obtain the anisotropic magnetoresistance. We decompose the temperature dependent anisotropic magnetoresistance in the temperature dependent k constants of Doring's equation. These constants show a reduction between T520 K and T5100 K, which reflects the observed decrease of the anisotropic magnetoresistance. We present argu- ments that the temperature dependence of the anisotropic magnetoresistance is most likely due to the change from defect-dominated scattering to phonon-dominated scattering, each of which has its own anisotropic magnetoresistance.