Deposition temperature influence on sputtered nanogranular magnetoresistive composites

Abstract Among different physical principles magnetic sensors for low magnetic field detection can be based on, granular giant magnetoresistances have been studied due to their high sensitivity to small field changes and gradual magnetoresistance change at low fields. Following this aim, nanogranular Ag–Co thin films, deposited by DC co-sputtering from Ag and Co targets at different deposition temperatures have been tested. Samples have been grown at room temperature, 100 and 200 °C and annealed in a mixture of N 2 and H 2 at 200 and 300 °C for 45 min. The samples that have shown the best performance have been subjected to two sets of measurements where an external field has been applied in-plane and perpendicular to the film plane. The best performance has been shown by the samples deposited at room temperature and annealed at 300 °C, reporting a maximum value of magnetoresistance of 16.7% at 1.4 T and a linear sensitivity of 63%/T between 0.04 and 0.07 T within a magnetoresistance range varying from 1.5% to 3% when subjected to an in-plane external field.