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| Surface Crystalline Modification for Asymmetric Giant Mngnetoimpedance Profile in Annealed Co-based Amorphous Ribbons |
| Journal of Magnetics, Volume 6, Number 3, 30 Sep 2001, Pages 86-89 |
Y. W. Rheem(Department of Materials Engineering, Chungnam National University), C.G. Kim*  (Department of Materials Engineering, Chungnam National University), C. O. Kim(Department of Materials Engineering, Chungnam National University), Y. Choi(Department of Materials Engineering, Sun Moon University) |
| Abstract |
| Microstructure modifications are investigated for annealed Co-based amorphous ribbon in vacuum and open air. X-ray diffraction (XRD) spectra for annealed sample in vacuum indicate atomic arrangements with initial nucleation of hcp-Co crystallite at 380 ℃ annealing temperature. However, the XRD spectra in samples with long annealing times of ta ≥ 300 min demonstrate sharp and good developed surface crystalline hcp-, fcc- Co and Co2Si phases. The giant magnetoimpedance (GMI) profile at 0.1 MHz displaying one-peak behavior in vacuum annealed samples at T = 380 ℃, irrespective of annealing time ta from 20 to 480 mim. For the annealed samples in an open air, the GMI profile shows two-peaks for ta = 20 min annealed sample. However, one of peaks disappears and an asymmetric GMI profile exhibits a drastic step-like change near zero field for ta ≥ 300 min. Such asymmetric GMI characteristics is related to the surface microstructures of fcc-Co, hop-Co and Co2Si crystalline phases. |
| Keywords: Co-based amorphous; giant magnetoimpedance; magneto-optic; surface crystalline |
| DOI: |
| Full Text: PDF |
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