Relationship between microstructure and field-induced anisotropy in cobalt-rich amorphous alloys after magnetic field annealing

S. C. Byeon, Chang Kyung Kim, K. S. Hong, R. C. O'Handley

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Abstract

We have made a comparative microstructural study of field annealed Co95-xFe5(BSi)x amorphous alloys using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). Until recently, it was generally assumed that amorphous magnetic alloys respond to field annealing by a process of local directional ordering which leaves the amorphous structure intact. However, striking differences in the microstructural morphology after field annealing were revealed for different glass former ratios B/Si. For high B/Si ratios, the surface crystals are predominantly fcc Co and demonstrate a high density of oxygen faults. For low B/Si ratios, the surface crystals are predominantly hcp Co and almost free of faults. Response to field annealing is proportional to the B/Si ratio and correlates with the presence of oxygen faults in surface crystals. These observations appear to be related to those of Nesbitt and Heidenreich in perminvar alloys where oxygen was found to be necessary for field annealing to be effective.

Original languageEnglish
Pages (from-to)58-65
Number of pages8
JournalMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Volume60
Issue number1
DOIs
StatePublished - 1999 May 31

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Amorphous alloys
Cobalt
Anisotropy
cobalt
crystal surfaces
Annealing
Magnetic fields
microstructure
Microstructure
anisotropy
annealing
Oxygen
magnetic fields
Crystals
oxygen
Transmission electron microscopy
transmission electron microscopy
leaves
Glass
Scanning electron microscopy

Cite this

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AU - Kim, Chang Kyung

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