Dissertation > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > The alloy learn with a variety of properties of alloys > Special physical properties of alloys > Special electromagnetic properties of alloy > Special magnetic properties of the alloy

Molten pulling prepared amorphous soft magnetic alloy fiber GMI effects

Author WuJiWen
Tutor TuGuoHua
School Nanjing Normal University
Course Condensed Matter Physics
Keywords Giant magneto-impedance Amorphous Soft magnetic GMI effect Legal system Penetration depth Physical mechanism GMI effects Application development prospects Inductive effect
CLC TG132.27
Type Master's thesis
Year 2003
Downloads 119
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Mohri et al FeCoSiB amorphous wire in 1992, the first to discover the giant magneto- impedance (GMI) effect . GMI effect GMI effect has the advantages of high sensitivity , low saturation magnetic field , faster response and good stability , great prospect , caused widespread concern in the field of magnetic sensors . Wire (wire or fiber ) like amorphous alloy material is one of the most significant material far GMI effect , taking into account the silk material , small size , low cost , and the firm texture and a broader application development prospects . The physical mechanism have been GMI effects have a preliminary understanding . In accordance with the AC frequency of the drive current through the sample , GMI can be roughly divided into three different frequency bands : (1) in the low frequency range of 1-10kHz , mainly caused by the magnetic effect of the inductance . (2) at higher frequencies until a few MHz , violent changes by an external magnetic field so that the effective magnetic permeability thereby cause changes of the magnetic penetration depth . (3) , since the ferromagnetic resonance , the depth of penetration in GHz of magnitude high frequency change dramatically and cause violent changes in the sample impedance . We selected the present study minimal melt pulling method prepared amorphous alloy fibers . By improving the existing single roll quenching preparation of amorphous strip means , making both the amorphous strip was prepared , and can melt drawing SYSTEM Maringer-Mobley experimental apparatus for preparing amorphous fibers , and succeeded in preparing a batch Co -and Fe-based amorphous alloy fiber , which has not been reported in the country . X - ray diffraction analysis , thermogravimetric analysis (TGA) and differential scanning calorimetry analysis (DSC) indicates that the fibers have a good amorphous properties . The longitudinal AC current and pulse current Joule heat treatment after the low-frequency GMI test : have a significant impact on the heat treatment of materials GMI effect change is very rich , and found some new phenomenon . The initial attempt to explain the results of the physical mechanism , deepened the understanding of the phenomenon of GMI GMI material contribute to superior exploration .

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