GROWTH AND GIANT MAGNETORESISTANCE PROPERTIES OF LA-DEFICIENT LAXMNO3-DELTA (0.67-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-1) FILMS

Epitaxial thin films of lanthanum-deficient LaxMnO3-delta (0.67 less than or equal to x less than or equal to 1) have been grown on (100) SrTiO3 substrates by pulsed laser deposition. The as-deposited films exhibit a ferromagnetic transition at temperatures ranging from 115 to 240 K, with the transition temperature (T-c) increasing with higher La deficiency. A sharp drop in resistivity and negative magnetoresistance is observed close to T-c, a behavior similar to that observed in divalent substituted La(1-x)M(x)MnO(3-delta) (M=Ba, Sr, Ca, Pb) films. Postannealing the films in O-2 reduces the resistivity and raises the T-c to values close to room temperature. A magnetoresistance value of 130% (Delta rho/rho(H)) has been obtained at 300 K at 4 T for a post-annealed film with x=0.75. (C) 1995 American Institute of Physics.