Permeability and giant magnetoimpedance in Co69Fe4.5X1.5Si10B15 (X=Cr, Mn, Ni) amorphous ribbons

Abstract

The magnetoimpedance (MI) has been measured in the amorphous ribbons of the soft ferromagnetic alloy Co69Fe4.5X1.5Si10B15 (X=Cr, Mn, Ni) as functions of frequency (f ). For all of the three samples, at low frequency, f⩽5 MHz, the MI ratio increases with increasing frequency, but the MI ratio decreases at high frequency, f⩾5 MHz. The MI profiles are not changed at low frequency regions of f⩽1 MHz in the amorphous ribbons. The MI ratio at high frequency of f=5 MHz becomes 57% in Co69Fe4.5Cr1.5Si10B15, but the MI ratio becomes 30% in Co69Fe4.5Mn1.5Si10B15 and Co69Fe4.5Ni1.5Si10B15. The MI ratio at f=10 MHz becomes 45% in Co69Fe4.5Cr1.5Si10B15 and the MI ratio becomes 23% in Co69Fe4.5Mn1.5Si10B15 and Co69Fe4.5Ni1.5Si10B15, respectively. The maximum values of field sensitivity are 2.7(X=Cr), 2.5(X=Mn), 2.2(X=Ni)%/Oe for f=5 MHz.