The specific heat of pure copper and of some dilute copper + iron alloys showing a minimum in the electrical resistance at low temperatures

Abstract

Abstract The specific heat of pure copper and of some dilute alloys of iron in copper, containing approximately 0.05, 0.1 and 0.2at. % iron, have been measured in the temperature range 0.4 to 30 °K. The electrical resistance of the copper + iron alloys has been measured from 0.4 to 80 °K. The alloys show specific-heat anomalies which probably extend from the absolute zero of temperature to the region of the minimum in electrical resistance. The entropy contents of the anomalies lie close to the value R In 2 per mole of iron suggesting that only two energy states of the iron ions are involved in the resistance minimum phenomena. The results are discussed in relation to existing theories.