Effect of iron doping on the properties of TbBaCo2O5.5 layered perovskite

The properties of the TbBa(Co2-xFex-)O5+delta (00.1, at which a concentration-dependent orthorhombic-tetragonal transition takes place. The orthorhombic composition with x=0.1 exhibits a transition from an antiferromagnetic to weak ferromagnetic state at a temperature T-i = 200 K on warming and at 160 K on cooling, and a transition from a weak ferromagnetic to paramagnetic state at T-N =304 K. A metal-insulator transition occurs at T-M = 348 K on warming. Transformation into a tetragonal phase (xgreater than or equal to0.12) leads to the disappearance of both the weak ferromagnetic state and the metal-insulator phase transition. Also, the Neel point drops. The orthorhombic and tetragonal phases coexist in the concentrational range (0.1