5 research outputs found
Evolution of structural and magnetic properties of Co–Fe based metallic glass thin films with thermal annealing
Ultra thin films based on CoFe were prepared from a composite target employing thermal evaporation. The
microstructure of the films was modified by thermal annealing. The relationship between microstructure and
magnetic properties of the films was investigated using techniques like glancing angle X-ray diffraction
(GXRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The GXRD and
TEM investigations showed an onset of crystallization of CoFe at around 373 K. The magnetic softness of the
films improved with thermal annealing but at higher annealing temperature it is found to be deteriorating.
Annealing inducedmodification of surface morphology of the alloy thin filmswas probed by atomic force microscopy
(AFM). Surface smoothening was observed with thermal annealing and the observed magnetic properties
correlate well with surface modifications induced by thermal annealingCochin University of Science & TechnologySurface & Coatings Technology 236 (2013) 246–25
Exchange bias effect in partially oxidized amorphous Fe–Ni–B based metallic glass nanostructures
The magnetic properties of amorphous Fe–Ni–B based metallic glass nanostructures were investigated. The nanostructures underwent a spin-glass transition at temperatures below 100 K and revealed an irreversible temperature following the linear de Almeida–Thouless dependence. When the nanostructures were cooled below 25 K in a magnetic field, they exhibited an exchange bias effect with enhanced coercivity. The observed onset of exchange bias is associated with the coexistence of the spin-glass phase along with the appearance of another spin-glass phase formed by oxidation of the structurally disordered surface layer, displaying a distinct training effect and cooling field dependence. The latter showed a maximum in exchange bias field and coercivity, which is probably due to competing multiple equivalent spin configurations at the boundary between the two spin-glass phases
Exchange bias effect in partially oxidized amorphous Fe–Ni–B based metallic glass nanostructures
The magnetic properties of amorphous Fe–Ni–B based metallic glass nanostructures were
investigated. The nanostructures underwent a spin-glass transition at temperatures below
100 K and revealed an irreversible temperature following the linear de Almeida–Thouless
dependence. When the nanostructures were cooled below 25 K in a magnetic field, they
exhibited an exchange bias effect with enhanced coercivity. The observed onset of exchange
bias is associated with the coexistence of the spin-glass phase along with the appearance of
another spin-glass phase formed by oxidation of the structurally disordered surface layer,
displaying a distinct training effect and cooling field dependence. The latter showed a
maximum in exchange bias field and coercivity, which is probably due to competing multiple
equivalent spin configurations at the boundary between the two spin-glass phasesCochin University of Science and TechnologyJ. Phys.: Condens. Matter 24 (2012) 256004 (8pp