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

We report the magneto-transport properties of La_0.7Ca_0.3-xSr_xMnO₃ (x=0 , 0.075, 0.1, 0.125, 0.15, 0.3) thin films on (100) LaAlO₃ substrates prepared by pulsed electron-beam deposition (PED). With increasing x from 0 to 0.3, both Curie temperature (TC) and metal-insulator transition temperature (TMI) 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 _MAX) at increased maximum MR temperature (T _MAX,) values. The film of x=0.125 exhibited extraordinary high MR _MAX value of 16% at 306 K. After post-annealing in a pure oxygen atmosphere at 900^degC, this film showed more enhanced MR _MAX of 18% at 325 K.