Effect of 57Fe ion implantation on magnetotransport in epitaxial La0.67Ca0.33MnO3 thin films

Epitaxial thin films of La0.67Ca0.33MnO3 were implanted with 30 and 100 keV Fe-57 ions at different fluence values to achieve a uniform implant distribution. The resistivity of the film increases as fluence increases, but the peak resistivity temperature T-p does not change significantly for the as-implanted sample. Annealing of the implanted samples at 950 degreesC allows recovery of the structural properties of the films and leads to interesting properties: increase of the peak resistivity and of the colossal magnetoresistance values, and decrease of T-p. The decrease in T-p is of similar to130 K, and the increase in resistivity is almost a factor of 28 as compared to the as-implanted sample. (C) 2003 American Institute of Physics.