Annealing effect on the giant magnetoresistance of La-Ca-Mn-O thin films

Thin films of perovskite-like (La,Ca)MnO/sub /spl delta// with [001] orientation were grown epitaxially on (100) MgO substrates by a simple facing-target sputtering technique. The as-deposited films already possess a significant low field giant magnetoresistance. Further post-annealing experiments on these samples indicate that the high electrical resistivity is not a prerequisite of the giant magnetoresistance effect.