The sensitive magnetoimpedance effect in Fe-based soft ferromagnetic ribbons

Abstract

A comprehensive analysis of magnetoimpedance (MI) phenomena in Fe-based nanocrystalline ribbons is presented in this paper. Giant MI responses have been observed in nanocrystalline samples annealed over the temperature range 490 and 600 • C. More than 400% increases of the MI ratio were obtained both in Fe 73.5 CuNb 3 Si 13.5 B 9 and in Fe 88 Zr 7 B 4 Cu ribbons. The sensitivity can reach a value larger than 60% Oe −1 in the field range 3-7.2 Oe at 800 kHz for Fe 73.5 CuNb 3 Si 13.5 B 9 ribbons. No MI effect was observed in an as-quenched amorphous Fe 88 Zr 7 B 4 Cu sample, because of its very low permeability. A mostly resistive feature was found in an as-quenched amorphous Fe 73.5 CuNb 3 Si 13.5 B 9 sample. The field dependences of the effective permeability show a typical transverse anisotropy property, and the development of the transverse anisotropy in naturally annealed Fe-based ribbons was analysed.

Magneto-impedance effect in Co-based metallic glass ribbons

“…For each sample the frequencies of maximum field sensitivity are chosen. These results agree with the previous findings [13][14][15]. 8 shows the plots of MI ratios and corresponding complex transverse permeability as a function of axially applied dc field for three ribbon samples.…”

“…Fig. Chen et al [14,15] states that the sharp decrease in transverse complex permeability with axially applied dc field is the prime reason of MI effect. In each case, it can be observed that there is a sharp decrease in permeability with dc field.…”

Magnetic properties and giant magnetoimpedance of nanocrystalline Fe92−xZr7BxCu1 ribbons

“…The typical three diffractory peaks of ␣-Fe bcc phase are presented for all annealed samples. By means of Schërrer's formula, the grain sizes for the five annealed ribbons of xϭ2, 4,6,8,10, are 20, 18, 14, 13, and 13 nm, respectively. The calculation of cubic lattice constant shows aϷ2.866 Å, which is the value of pure ␣-Fe.…”

“…[2][3][4][5][6] Recently, because of the higher permeability, lower coercive force, and slightly positive magnetostriction ( s Ϸ2ϫ10 Ϫ6 ) of Fe-based nanocrystalline FeCuNbSiB alloys, more attention has gradually been paid to the GMI effect of them. [7][8][9] A large MI ratio of more than 400% was found in nanocrystalline Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 ribbons. Under the longitudinal field range 240-560 A/m, the MI ratio sensitivity larger than 0.75% ͑A/m͒ Ϫ1 ͑60% Oe Ϫ1 ͒ can be obtained at frequency f ϭ0.8 MHz.…”

“…Value of the (⌬Z/Z) max and ͓d(⌬Z/Z)/d(H)͔ max for the Fe 92Ϫx Zr 7 B x Cu 1 ribbons (xϭ2,4,6,8,10). ͑The unit of frequency f is MHz.͒ ϭ6.5) ( f ϭ4.5) ( f ϭ4.5) ( f ϭ6.5) ( f ϭ6.5) ͓d(⌬Z/Z)/d(H)͔ max % ͓͑A/m͒ Ϫ1 ͔ ( f ϭ5.5) ( f ϭ6.5) ( f ϭ6.5) ( f ϭ10.5) ( f ϭ10.5) ͓d(⌬Z/Z)/d(H)͔max is the maximal value of the derivative of the ⌬Z/Z vs H L curve.…”