Change in electrical resistivity during continuous heating in ordered and disordered Cu-15 at.% Pd alloys

Abstract The electrical resistivity of ordered and disordered Cu-15 at.% Pd alloys is measured and the resistivity changes during continuous heating are compared with results obtained by differential thermal analysis. The electrical resistivity of both samples increases anomalously near to the order-disorder transition temperature Tc , being higher than that atTc and then dramatically decreases just below Tc , exhibiting a sharp peak on the electrical resistivity curve. Also, on the electrical resistivity curve of the disordered sample, a further peak is formed at a lower temperature than the peak formed just below Tc . Differential thermal analysis reveals that the resistivity changes involving the anomalous increase correspond generally to the exothermic and endothermic peaks for ordering and disordering of the samples during continuous heating. Combining such information with antiphase domains (APDs) structure and selected-area diffraction spot intensities observed by transmission electron microscopy, it is confirmed that the anomalous increase in the resistivity observed in Cu-15 at.% Pd alloys is related to development of long-range order, independent of APD size.