Influence of V and Mn doping on the electrical transport properties of a Cr + 1.2 at.% Ga alloy

Measurements of the electrical resistivity (ρ) of a Cr + 1.2 at.% Ga alloy doped with V or Mn, are reported in the temperature range 6-900 K. These measurements were complimented with thermal expansion (α) measurements for the undoped Cr + 1.2 at.% Ga alloy in the temperature range 77-450 K. The measurements show interesting behaviour with dopant concentration in that the residual resistivity (ρresidual) does not vary smoothly with dopant concentration as expected. On the contrary, ρresidual shows three peaks as a function of dopant concentration. This behaviour is ascribed to impurity resonant scattering effects which are included in a theoretical model used to explain the observed temperature dependence of the resistivity for these alloys. The resistivity and thermal expansion coefficient of the Cr + 1.2 at.% Ga alloy behaves anomalously close to the ISDW-CSDW phase transition temperature (TIC). The temperature derivative of the resistivity shows a minimum while the α-T curve shows a peak at TIC in contrast to what is expected. The magnetic phase diagram of the (Cr + 1.2 at.% Ga)(V, Mn) alloy system is constructed from the results of the measurements.