Annealing of thin magnetoresistive permalloy films

The figure of merit of magnetoresistive Permalloy thin films, which are commonly used for bubble domain sensors, is shown to improve considerably after annealing treatments. This improvement is caused by a lowering of the electrical resistivity, due to particle size and grain growth with activation energies of 0.70 ± 0.05 eV and 1.86 ± 0.15 eV, respectively. Comparisons indicate that thin permalloy films, which are deposited at 250°C and subsequently annealed, are superior as sensor materials to those deposited at 325°C.