The domain wall pinning and exchange coupling induced by surface crystallization in field-annealed cobalt-rich amorphous alloys
✍ Scribed by C.K. Kim; R.C. O'Handley
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 653 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0921-5107
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✦ Synopsis
Attempts were made to correlate magnetic properties of ('o-rich amorphous alloys such as domain wall pinning anti exchange coupling with microstructural changes during field annealing. It was observed that M-H loops of first annealed material under longitudinal field showed weak exchange anisotropy duc to coupling of the amorphous alloy to a semi-hard Co-rich crystalline surface layer. After second annealing without magnetic field, re-entrant magnetization behavior was observed.
These alloys show appreciable surface crystallization during annealing Striking differences in the microstructural morphology were revealed for different glass former ratios B.'Si. For high B Si ratios, the surface crystallites arc predominantly, f.c.c. ('o and show at high density' of oxygen fauhs. For low B Si ratios, the surlhce crystallites are predominantly h.c.p. Co and almost flee of faults.
The degrcc of exchange coupling is proportional to the B Si ratio and correlates with the presence of oxygen fiaults in surlhce crystallites. It is also observed that there is at good correlation between domain wall pinning field and thickness of crystalline ('o layer.