Frequency-modulation-type MI sensor with nanocrystalline ribbon core

A longitudinally driven giant magneto-impedance (GMI) effect in the tensile-stress-annealed nanocrystalline Fe73Cu1Nb1.5V2Si13.5B9 ribbons was investigated and a frequency-modulation (FM)-type MI sensor utilizing the effect has been developed. A highest sensitivity of 42%/Oe for the sensors was obtained. The sensitivity and linear range of the sensors can be modified by inducing suitable transverse magnetic anisotropy using longitudinal tensile stress annealing. A linear FM-MI sensor in the range of ±2 Oe was constructed with a sensitivity of 15%/Oe.