Molten pulling prepared amorphous soft magnetic alloy fiber GMI effects
|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|
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 .