Thermal Sprayed Thick-Film Anisotropic Magnetoresistive Sensors.

Ni80 Fe20 and Ni80 Co20 alloys anisotropic magneto- resistive sensor films were deposited by plasma spray. The resistivity (ρ) of the films is determined to be 40-70, μΩcm in the as-sprayed state. The oxygen impurity dissolved in the metal acts as a strong scattering center and results in higher resistivity. The ρ of sensor film improves significantly with thermal annealing up to 500 °C and it remains constant for further increase in temperature. The dissolved oxygen precipitates out as oxide phase during heat treatment and that reduces the scattering. The ρ values are 19 and 22 μΩ·cm for permalloy and NiCo alloy turns, respectively, which are close to bulk values. The anisotropic magnetoresistance (AMR) effect is found to be increased by a factor of 2 in both the permalloy and the NiCo sensors. The Δ R/R values are increased from 2.0% to 4.0% and 2.6% to 5.8%, respectively, for permalloy and NiCo sensors. [ABSTRACT FROM AUTHOR]