Magnetoresistance and magnetic properties of La-1-x square xMnO3-delta thin films

Epitaxial thin films of La(1-x)square(x)MnO(3-delta)(0 less than or equal to x less than or equal to 0.33) where square is a vacancy have been grown on (100) SrTiO3 substrates by pulsed laser deposition. The Ianthanum deficiency results in self doping of the system without the need for divalent ion substitution. Both the films and the bulk targets used for deposition were ferromagnetic and showed giant magnetoresistance (GMR). The films increased in saturation magnetization M(s) and Curie temperature T-c with increasing x. The T-c, however, was about the same as found in Ca-x substitutions. Bulk samples showed little change in M(s) and T-c with vacancy concentration. M(s) in bulk samples is about half the value found in the films which have theoretical saturations for x>0.2. GMR in the films is a few hundred percent but the bulk values are 25% at H=1.8 T. (C) 1996 American Institute of Physics.