Electrical Resistivity of Some Chromium-Silicon Alloys

Electrical resistivity (ρ) of chromium-silicon alloys, containing 0.4 6 , 0.9 0 , 1.3 7 , 1.8 5 , 2.7 4 , 3.1 9 , and 3.6 7 at.% silicon, has been measured over the temperature ( T ) range of 4 to 320°K. It was found that silicon markedly lowers the Néel temperature of chromium as determined from the ρ vs. T curves for the chromium alloys with 0.4 6 , 0.9 0 , and 1.3 7 at.% silicon. In addition, the alloy containing 1.3 7 at.% silicon show a sharp step-type anomaly at about 240°K. A similar anomaly occurs at lower temperatures in alloys containing 1.8 5 and 2.7 4 at.% silicon. In alloys with higher silicon content this anomaly is less-well defined. The dependence of the Néel temperature upon silicon concentration is briefly discussed from the viewpoint of the Fermi surface of chromium and the theory of Fedders and Martin. The effect of the energy gaps, associated with the onset of the antiferromagnetic ordering in the dilute chromium alloys, on the electrical resistivity just below the Néel temperature, is not solely responsible for the observed behavior. A minimum in the ρ vs. T curves at low temperatures is observable for all alloys except those containing 3.1 9 and 3.6 7 at.% silicon. This behavior is similar to that found in chromium-germanium solid solutions and appears to be due to either the Kondo or the Kim effect.