ANOMALIES OF HALL-EFFECT AND MAGNETORESISTANCE IN OXYGEN-DEFICIENT LA(2 3)A(1/3)MNO(3-DELTA) EPITAXIAL LAYERS/

The effect of oxygen disorder on the magnetic moment, resistivity, Hal l effect and magnetoresistance of oxygen deficient La(2/3)A(1/3)MnO(3- delta) epitaxial thin films has been studied in magnetic fields up to 20 T and temperatures down to 4.2 K. Our results show, that rho(T, H) of these thin films depends on delta but differs in detail from that o f equivalent nonstoichiometric bulk samples. In particular, changes in sign and magnitude of the magnetoresistance Delta rho/rho occur which suggest positive and negative shifts of a magnetic order-oder transit ion temperature in a magnetic field, dT(1)/dH, depending on delta. The Hall measurements give a hole carrier concentration of about 3 x 10(2 1) cm(-3) for near stoichiometric compounds.