Magnetoresistance in the hard/Cu/soft sandwiches: Dependence on layer thickness and field annealing

摘要

NiFe(2nm)/Cu(t_(cu))/Co(1.5nm) sandwiches were deposited on Ta buffer layer by magnetron sputtering method. Small angle X-ray diffraction analysis was made to investigate the structural characterizations of the sandwiches. It has been obtained that MR value showed a maximum at t_(Cu)=2nm when Cu spacer thickness changed, which is contributed by the effect of shutting and interlayer coupling. The Cu layer was deposited at two different rates. Larger MR ratio was observed with a lower deposition rate. The result was discussed in terms of magnetic reversal fields. In addition, the sandwiches were subjected to field annealing at different annealing temperatures. MR ratio has exhibited a largest increase after annealing at 175°C with a magnetic field of 750Oe applied.