Magnetostatic properties of heterogeneous Co-based amorphous/crystalline phases

Off-diagonal magnetoimpedance in field-annealed Co-based amorphous ribbons

“…The characteristics of the amorphous and crystalline phases in field-annealed Co-based amorphous ribbons have been analyzed separately by means of the magneto-optical Kerr effect, and the shift of loop for amorphous phase within low-field region has been revealed due to the exchange coupling. 11 The coupling between the crystalline and amorphous phases produces an effective bias field resulting in the asymmetry in the dc magnetization that is responsible for the asymmetric GMI in field-annealed ribbons. 6,9 At sufficiently low frequencies, the GMI profile exhibits a drastic steplike change in the impedance near zero field (the so-called "GMI valve"), and at high frequencies, the field dependence of the impedance shows asymmetric two-peak behavior.…”

The effect of surface crystalline layers on asymmetric off-diagonal magnetoimpedance in field-annealed CoFeSiB amorphous ribbons

“…Similar to the GMI effect measured as the field-dependent voltage drop across the ribbon [5,6], the asymmetry has been attributed to the surface crystallization after annealing. The development of the surface crystalline layers has been confirmed by means of the X-ray diffraction spectra [6] and the magneto-optical Kerr effect [7]. The coupling between the amorphous bulk and the crystalline layers results in the asymmetry in the GMI response.…”

Surface crystallized Co66Fe4B15Si15Životský1, Postava2, Kraus3 et al. 2005Journal of Magnetism and Magnetic Materials7010View full textAdd to dashboardCite

“…The longitudinal magneto-optical Kerr effect was applied for investigation of the near-surface magnetic properties of field-annealed amorphous Co 66 Fe 4 …”

“…GMI asymmetry originates from exchange coupling between the surface crystalline and bulk amorphous phases [2,3]. Although these materials are widely used, change of their magnetic and electric properties during annealing in the air has not been understood well [4,5].…”