ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The evolution of the magnetic domain patterns and the giant magnetoimpedance (MI) effect in the Fe73.5Cu1Nb3Si13.5B9 amorphous ribbons are studied as a function of the annealing time ta at 550 °C. It is shown that by annealing at 550 °C for ta from 1 to 150 h, very fine nanocrystalline bcc-FeSi grains are homogeneously formed in the amorphous matrix. Although with increasing ta the grain size remains very fine (≤11 nm), the coercivity Hc increases rapidly from 0.0014 Oe for ta=3 h to 1.67 Oe for ta=150 h. For the nanocrystalline ribbons with ta=3 h, the domain structure is characterized by a few broad longitudinal together with some broad transverse domain patterns, connected to the minimum coercitive field. With increasing annealing time ta≤10 h, only transverse domain patterns are observed and the transverse domain width gradually becomes narrow. Considering the different magnetic softness, domain structure, and magnetization process, various types of the MI effect are observed in these nanocryastalline ribbons. A maximum value for the MI ratio ΔZ/Z=[Z(H)−Z(Hmax)]/Z(Hmax), of about 400%, and a maximum sensitivity of the MI ratio, of about 170% Oe−1, are obtained in the nanocrystalline samples annealed at 550 °C for 3 and 10 h, respectively. These maximum MI effects are related to the optimum combination of soft properties with the transverse domain patterns. It is revealed that the magnetic softness together with the domain width of a transverse domain pattern are the key parameters to realize a large MI ratio. © 2001 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1331649
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