Magnetoresistance of FePt nanograins embedded in carbon matrix

We studied the magneotransport properties of granular films of FePt/C which were fabricated by using DC magnetron co-sputtering technique. Films were made at the sputtering pressures of 30 and 15 mTorr, and with sputtering powers of 80 and 60 W for each pressure. A large magnetoresistance of 6% at 2 K was observed only for the film made at 80 W and 15 mTorr. Other magnetoresistance values were all below 1%. We also discussed the influence of carbon matrix on the giant magnetoresistance.