Anomalous magnetic and electrical transport behaviour in intermetallic Co<inf>58.5</inf>Ga<inf>41.5</inf>

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 CoxGa100-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 Co58.5Ga41.5 composition prepared under different process conditions to elucidate magnetic ground state.