Large magnetoresistance anomalies in Dy₇Rh₃

Abstract

The compound Dy₇Rh₃ ordering antiferromagnetically below (T_N=) 59 K has been known to exhibit a temperature (T) dependent electrical resistivity (ρ) behaviour in the paramagnetic state unusual for intermetallic compounds in the sense that there is a broad peak in ρ(T) in the paramagnetic state (around 130 K) as though there is a semiconductor to metal transition. In addition, there is an upturn below T_N due to magnetic super-zone gap effects. Here we report the influence of external magnetic field (H) on the ρ(T) behaviour of this compound below 300 K. The rise of ρ(T) found below T_N could be suppressed at very high fields (» 60 kOe), thus resulting in a very large magnetoresistance (MR) in the magnetically ordered state. The most notable finding is that the magnitude of the MR is large for moderate applications of H (say 80 kOe) in a temperature range far above T_N as well, which is untypical of intermetallic compounds. Thus, this compound is characterized by large MR anomalies in the entire T range of investigation.