Magnetic and transport properties of La0.7Sr0.3Mn1−xTixO3 (0 ⩽ x ⩽ 0.5) films prepared by chemical solution deposition

Abstract

La0.7Sr0.3Mn1−xTixO3 films (0 ⩽ x ⩽ 0.5) were fabricated using chemical solution deposition. It was found that with an increase in Ti content, the lattice constant was first increased due to the substitution of Mn4+ with Ti4+, and then it tended to decrease when x ⩾ 0.3 due to the substitution of Mn3 + by Ti4+ with a larger ionic radius, as well as when excess oxygen was introduced. With the increase in x, the Curie temperature was decreased and broadened; however, it was found that all the films showed ferromagnetic properties at 300 K, which indicated that the excess oxygen played an important role. The transport properties showed that with an increase in Ti content the resistivity increased and the insulator–metal transition tended to a lower temperature due to the depression of the double exchange and the dilution of the Mn3 +–O–Mn4+ network. Moreover, the temperature dependence of magnetoresistance (MR) results showed that with the Ti content increasing, the maximum MR increased and the transition was broadened suggesting that it is useful to tune the MR behaviour through Ti doping, and when x ⩽ 0.1 the derived films showed no obvious MR at low temperature; however, when x = 0.3, the film did show obvious MR at low temperature.