Effect of partial order on galvanomagnetic transport properties of ferromagnetic PdFe and PdCo alloys

The effect of ordering on the galvanomagnetic properties such as the anomalous Hall conductivity (AHC) and the anisotropic magnetoresistance (AMR) ratio is studied using recently developed formalism which takes into account both the Fermi surface and Fermi sea contributions to the conductivity tensor. As a case study we have considered Pd-rich L1 sub(2)- Pd sub(70)Fe sub(30) alloy and disordered fcc-Pd sub(1-x)Co sub(x) alloy with a weak partial L1 sub(0) and L1 sub(2) orderings which can exist around stoichiometric compositions. We have found a nonnegligible effect of the Fermi sea term for the Pd-rich PdFe alloys while its effect for completely disordered fcc-PdCo alloy is small. The most important effect of inclusion of a weak partial order for fcc-PdCo alloys in theoretical calculations is improvement of the agreement between theory and experiment for the resistivity but first of all for the AMR ratio. An enhancement of the AMR ratio due to the layerlike L1 sub(0) ordering brings calculated and experimental values into a good agreement missing in the disordered alloy. The effect of the isotropic L1 sub(2) ordering on the AMR values is weak. Finally, the effect of the ordering on the resistivity and the AHC is much weaker, although observable.