Transport properties of antiferromagnetic superconductors

Abstract

Transport properties of antiferromagnetic superconductors with T{sub N} < {Tc} were investigated. Detailed numerical, results are given for SmRh{sub 4}B{sub 4} by using the following model. The paramagnetic phase (T{sub N} < T < {Tc}) is described by using Abrikosov-Gorkov theory of magnetic ions in an ordinary superconductor. In the AF phase (T {le} T{sub N}), the effects of the molecular field H{sub Q}(T) and the elastic scattering of conduction electrons from spin fluctuations are included. Expressions for H{sub Q}(T) and the scattering rate from spin fluctuations were derived. The aim was to see if properties are enhanced or depressed by the AF ordering occurring below T{sub N}. It is found that whereas the electronic thermal conductivity K{sub s}, nuclear spin relaxation rate R{sub s}, and the longitudinal ultrasonic attenuation a{sub s}, are depressed by the AF ordering, the inverse of the magnetic penetration depth, ({lambda}(T)){sup {minus}1}, is enhanced below T{sub N}. The effect of all types of impurities is included in the study. Theoretical results for K{sub s} and ({lambda}(T)){sup {minus}1} agree with the experimental values for SmRh{sub 4}B{sub 4} (experimental data for other properties are not available in literature). In the above, T{sub N} is the Neel temperaturemore » and {Tc} is superconducting transition temperature.« less