Abstract
The electrical resistivity of Cu-15 at.%Pd alloys ordered and disordered by annealing at various temperatures and immediately quenched, is measured, and differential scanning calorimetry (DSC) of each sample is performed to obtain the order parameters at various temperatures. Electrical resistivity measurement reveals that the anomalous increase in the electrical resistivity just below the order-disorder transition temperature Tc is commonly observed in all samples, irrespective of the quenching temperature. By the DSC measurement of each sample it is also shown that the change in the order parameter S with the quenching temperature is very similar to that reported in other superlattice alloys such as Can. By relating the residual resistivity and the temperature coefficient of the resistivity to S for each sample, it is derived that the residual resistivity decreases approximately in proportion to S 4.6, and the temperature coefficient increases properly in proportion to S 2 as the temperature is raised. Further, it is found that the resistivity versus temperature curve calculated from the change in the S during heating using the above relationships is in good agreement with the experimental curve obtained directly by the resistivity measurement. By combining this fact with the antiphase domain structure reported previously by the present authors, it is concluded that the anomalous increase in the resistivity just below Tc in Cu-15 at.%Pd alloys can be ascribed mainly to the larger temperature coefficient of resistivity in the ordered state than in the disordered state.