Electrical resistivity of PdFe alloys

The electrical resistivity p of a series of ferromagnetic PdFe alloys varying in composition from 1 to 12 at.% Fe was measured from 4.2 to 300 degrees K. The data were analyzed by subtracting from the measured rho values, the value of the electrical resistivity of a sample of 99.999 +%-purity Pd at each temperature. From these values of the incremental resistivity Delta rho we have obtained the tempera tu re-dependent part by subtracting its limiting low temperature value (at 4.2 degrees K). The resulting temperature- and concentration-dependent resistivity Pm has the following properties: For alloys of Fe concentration c greater than or similar to 2 at.%, rho(m)-proportional to AT(2) up to about 40 degrees K in all but the highest-concentration alloys studied. Above ibis temperature we find a T-3/2 law up to the ferromagnetic ordering temperature T-C except in alloys with c greater than or similar to 6 at.%, where the temperature dependence is faster above approximate to 0.7 T-C. A 1 at.% alloy sample had a low-temperature behavior intermediate between the T-2 behavior of the higher-concentration alloys and the T-3/2 behavior observed in alloys with Fe concentration less than 1 at.%. The coefficient A of the low-temperature T-2 dependence of rho(m) increases approximately linearly with Fe concentration, and at 2 at.% is about seven times as large as the value found in pure Pd. These results suggest that electron-magnon scattering is the dominant scattering mechanism determining rho(m). Our data, above 2 at.% Fe, are best interpreted in terms of a model in which the PdFe alloys are considered to be approximately magnetically homogeneous with an effective, concentration-dependent "s-d" exchange interaction. In terms of this model, the expected correlation between the coefficient A and the spin-wave excitation spectrum, at low temperatures, is shown to exist.