Low-temperature resistivity and thermoelectric power controlled by defects in the USb antiferromagnet

Abstract

The resistivity ρ(T), magnetoresistivity, magnetization and thermoelectric power S(T) of several USb crystals have been examined in the temperature range 0.03–300K, in magnetic fields up to 14T. The resistivity ratio (RR)(=ρ(300K)/ρ(4.2K)) of examined crystals ranged from 1.6 to 13. It was found that defects, which decrease the RR, contribute both to ρ(T) in the shape of a temperature dependent Kondo-like component and to S(T) by means of a peak-like component. The ρ(T) curve shows a maximum below 2K and a minimum between 8 and 14K, depending on the RR. S(T) reaches a maximum at 40 K, which is as large as 40μVK⁻¹ for the sample with RR = 13. The low-temperature ρ (T) behaviour indicates a Kondo temperature of 37 K, fairly close to the temperature of the S(T) maximum. The origin of the Kondo-like behaviour of the resistivity and the thermoelectric power of USb crystals at low temperatures is discussed.