Study of electrical and magnetic properties of RE doped layered cobaltite thin films

Abstract Thin films of layered perovskites Sr 1.5 RE 0.5 CoO 4 (RE = La, Gd) were grown on MgO (0 0 1) substrate using pulsed laser ablation method. Structural, electrical and magnetic properties of single phase oriented films were studied. Films reveal semiconducting behavior in the entire measured temperature range. The films show thermally activated behavior at high temperature regime, with a higher value of activation energy for SGCO than that for SLCO. The low temperature behavior is well fitted with 3D-variable range hopping mechanism. Both films showed negative magneto-resistance measured in temperature range of 10–200 K. The value of MR is large for SGCO film as compared to its bulk counterpart as well as SLCO film, suggesting its high potential in the spintronics applications. A pinch-shaped M−H behaviour as observed in both the films, suggests the presence of two-magnetic phases. Occurrence of pinch-shape behaviour is although in line with that of SLCO bulk counterpart, interestingly, it was absent in SGCO polycrystalline powder. It suggests major role of film growth kinetics in modifying the magnetic properties in cobaltites.