Anomalous magnetic and electrical transport behaviour in intermetallic Co58.5Ga41.5

Equi-atomic intermetallic Co-Ga compound exhibits unusual properties, such as, non-metallic electrical transport and weakly magnetic behavior . Electronic band structure calculations suggest the presence of deep psuedogap in the density of states near Fermi level . As the cobalt concentration varies over 50-60 at% it presents an interesting magnetic phase diagram along with drastic variation in electronic properties across a critical concentration (x~58) in Co_xGa_100-x alloy system . The magnetic characteristics observed in these alloy were attributed to antisite defects [1, 2] . Despite several works on this alloy no clear consensus emerged on the nature of magnetic phase transitions observed and the magnetic ground state . A detailed analysis of thermal and magnetic field (H) dependence of magnetization (M) can throw light on magnetic ground state and the origin of anomalous behavior at critical composition . In this work we present dc magnetization, magnetoresistance (MR) and specific heat study of Co_58.5Ga_41.5 composition prepared under different process conditions to elucidate magnetic ground state.