Colossal magnetoresistance in Sm1-xSrxMnO3 films

Magnetotransport properties were investigated for Sm1-xSrxMnO3 films that were prepared by the pulsed laser deposition technique. Application of a magnetic field causes a huge change in the resistivity for x=0.45, 0.50, and 0.55, in some cases exceeding five orders of magnitude. Measurement of the magnetization curve at low temperature which is removed after loading of a high magnetic field (5T) suggests the existence of the antiferromagnetic correlations. In accord with this, the magnetoresistance shows an irreversible behavior against the field sweep. The results imply that the colossal isothermal magnetoresistance in the thin films, of which the hole concentration is of a commensurate value of around, x= 1/2 has the same origin as the magnetic-field-induced first-order transition reported for the single crystals that is the magnetic-field-induced melting of the charge-ordered stale. (C) 1996 American Institute of Physics.