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 eq ual to x less than or equal to 0.33) where square is a vacancy have be en grown on (100) SrTiO3 substrates by pulsed laser deposition. The Ia nthanum deficiency results in self doping of the system without the ne ed for divalent ion substitution. Both the films and the bulk targets used for deposition were ferromagnetic and showed giant magnetoresista nce (GMR). The films increased in saturation magnetization M(s) and Cu rie temperature T-c with increasing x. The T-c, however, was about the same as found in Ca-x substitutions. Bulk samples showed little chang e 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 saturat ions 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.