Transverse domain structure related giant magnetoimpedance in nanocrystalline Fe73.5Cu1Nb3Si13.5B9 ribbons

Abstract

A sensitive field- and frequency-dependent magnetoimpedance (MI) has been observed in nanocrystalline Fe73.5Cu1Nb3Si13.5B9 ribbons. A maximum value for the MI ration ΔZ/Z=[Z(H)−Z(Hmax)]/Z(Hmax), of more than 400% was obtained in these nanocrystalline ribbons (annealed for 3–5 h at 550 °C). A peak in the field dependence of the MI ratio ΔZ/Z was observed in nanocrystalline samples, but not in the as-quenched amorphous samples. The sensitivity attained a value larger than 60% Oe−1 in the field range 3–7 Oe at 800 kHz for the nanocrystalline ribbons. Domain observation experiments show that the transverse domain structure observed in nanocrystalline samples is responsible for their giant MI effects, and the domain wall movements in the transverse domain pattern region are dominant during the initial magnetization processes in both longitudinal and transverse directions of the applied field. The correlation between the magnetization processes and the giant MI effects is discussed briefly based on the view of a modified skin effect.

Stress level in Finemet materials studied by impedanciometry

“…This type of domain structure has been previously observed in Finemet materials, as described in Ref. 5. The other samples probably do present this kind of domain structure, but the low value impedes the identification of the domain families.…”

Correlation between MI Effect and Transverse Anisotropy in Stress-Annealed Nanocrystalline Alloys: A M�ssbauer Effect Study

“…Recently, with the application of a tensile stress or a transverse magnetic field during annealing, several Fe-based nanocrystalline alloys, such as Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 , Fe 73 Cu 1 Nb 1.5 V 2 Si 13.5 B 9 and Fe 73 Cu 1 Nb 1.5 Mo 2 Si 13.5 B 9 , have been found capable of obtaining not only a transverse magnetic structure but also a large magneto-impedance (MI) effect [3][4][5][6]. The fact that the transverse magnetic anisotropic is an essential factor for large MI effect has been explained theoretically by domain wall movements and moment rotations [4][5][6][7]. It has also been experimentally demonstrated by MI effect measurements [3,[5][6][7], and the transverse domain structure has been directly observed by a combination of transmission electron microscopy, electron diffraction, and magneto-optical Kerr effect microscopy [4].…”

Analysis of asymmetric property with DC bias current on thin-film magnetoimpedance element

“…[5][6][7][8] Its application as a compass in mobile phones was commercialized, and it is still being refined to realize a higher sensitivity sensor 9 compared to other types of magnetic sensors. Though amorphous wires and ribbons are mainly used, [10][11][12][13][14] they are not suitable for the miniaturization of sensor elements. Thin-film magnetoimpedance elements are more compatible with miniaturized integrated electronic devices; however, the sensitivity of the elements is less than that of wires and ribbons.…”