Strain Relaxation And Magnetoresistance Of La0.7ca0.3mno3 Film Deposited On Mgo Substrate

La0.7Ca0.3MnO3(LCMO) thin films with the thickness ranging from 5 nm to 200 nm were deposited on (001)-oriented single crystal MgO substrate by 90 degrees off-axis radio frequency magnetron sputtering. Grazing incidence X-ray diffraction technique, combined with normal X-ray diffraction, was applied to study the lattice strain and strain relaxation in LCMO films. The magnetoresistance of films were measured by means of standard four-probe technique. The results indicated that the microstrain of LCMO/MgO film began to relax when the film thickness is less than 5 nm. The LCMO film is fully strain-relaxed with thickness larger than 100 nm and exhibit LCMO bulk-like magnetoresistance properties, i.e. with relatively lager magnetoresistance ratio and higher peak temperature of magnetoresistance.