Magneto-Transport Properties of $hbox{La}_{0.7}hbox{Ca}_{0.3-{rm x}}hbox{Sr}_{rm x}hbox{MnO}_{3}$ Thin Films Deposited by Pulsed Electron Deposition

摘要

We report the magneto-transport properties of ${rm La}_{0.7}{rm Ca}_{0.3-{rm x}}{rm Sr}_{rm x}{rm MnO}_{3}$ ($x=0$ , 0.075, 0.1, 0.125, 0.15, 0.3) thin films on (100) ${rm LaAlO}_{3}$ substrates prepared by pulsed electron-beam deposition (PED). With increasing $x$ from 0 to 0.3, both Curie temperature $(T_{C})$ and metal-insulator transition temperature $(T_{MI})$ of the films were increased from 206 and 212 K to 339 and 366 K, respectively. Except $x=0.125$ film, with increasing $x$ , all other LCSMO films showed a tendency of gradual decrease in the maximum MR ratios $(MR_{rm MAX})$ at increased maximum MR temperature $(T_{rm MAX,})$ values. The film of $x=0.125$ exhibited extraordinary high $MR_{rm MAX}$ value of 16% at 306 K. After post-annealing in a pure oxygen atmosphere at 900$^{circ}{rm C}$, this film showed more enhanced $MR_{rm MAX}$ of 18% at 325 K.