The calculation of the residual stress tensor components in glass-coated amorphous ferromagnetic microwire is carried out on the basis of the theory of viscoelasticity. The approach takes into account the relaxation of the stresses both in a metallic core and a glass shell of the wire within a certain temperature interval near the point of the wire's vitrification. The distribution of the residual stresses is investigated as function of mechanical characteristics of metallic core and glass shell at different ratios of the metallic core radius to the total wire radius. The magnetic behaviour of a glass-coated amorphous microwire with small negative magnetostriction is analysed and is shown to be consistent with the experimental data.

No abstract

The residual stress-tensor components in amorphous ferromagnetic wire produced by an 'in-rotating-water' spinning process are calculated on the basis of the theory of viscoelasticity. The viscoelastic behaviour of the solidifying wire near the point of vitrification is studied and the effect of the relaxation process on the residual quenching stresses is clearly elucidated. The radial dependence of the residual stress-tensor components obtained is consistent with the magnetic behaviour of amorphous wire with small negative saturation magnetostriction. The residual stress amplitude is investigated as the function of wire radius and the parameters of the cooling process.

The magnetization reversal of Cu/NiFe and Nb/NiFe composite wires carrying AC current is studied. The frequency spectrum of a voltage induced in a pick-up coil wound around the wire is analyzed. The frequency spectrum is shown to consist of even harmonics within a wide range of AC current amplitudes and longitudinal DC magnetic fields. The strong dependencies of the harmonic amplitudes on the DC field are found. The results obtained may be of importance for the design of weak magnetic field sensors.

Abstracl-The permalloy-copper composite wires consisting of high conductivity Cu Inner core and NiFe outer shell were fabricated by a modified cold-drawn technique. The diameter of the Cu inner core was in 20 -120 pm range, and the NiFe outer shell was 10-40 pm thick. The composite wires exhibit soft magnetic behavior and the giant magnetoimpedance effect. The amplitude of the giant magnetoimpedance at high frequencies is comparable to that of conventional amorphous wires and significantly larger than that ofNiFe wires without Cu inner core. Nevertheless, the sensitivity ofthese wires does not reach the theoretical predictions based on the simple models for composite wires with the axial or circumferential types of magnetic anisotropy.