Transport and magnetic properties of La_1−xBa_xCoO₃

Abstract

We have systematically investigated transport, magnetic, and structural properties of La_1−xBa_xCoO₃ in the range of doping 0 < x ≤ 0.55 . In this system, the metal-insulator transition is observed to be coincident with the onset of ferromagnetic (FM) ordering at x = 0.20 . Well below Curie temperature T C , ρ exhibits T 2 behavior whereas over a temperature interval just below T C , it shows T 4 dependence due to the scattering of charge carriers by magnetic fluctuations. For x < 0.20 , the low temperature magnetic property is dominated by a spin-glass- or cluster-glasslike phase. The role of ionic size mismatch on the above mentioned physical properties has also been investigated by partially substituting La with Nd and Ba with Sr for a fixed doping. A phase diagram, the dependence of transition temperatures on doping ( x ) , has been constructed for La_1−xBa_xCoO₃ from this study.