During the preparation process of the glass-covered magnetic aInorphous wires, axial, radial, and azimuthal internal stresses are induced, determining their magnetic properties. We have proposed a calculation method of the internal stresses induced during the solidification of the metal and during the cooling from the solidification temperature to room temperature due to the difference between the thermal expansion coefficients of metal and glass. For Fe77 QSi7 5B]5 glass-covered amorphous wires we found internal stresses of about 10 Pa. The values and distribution of these stresses depend on the radius of the metal and on the thickness of the glass cover. The stress distribution coupled with the specific high positive magnetostriction leads to an easy axes distribution associated with a magnetic domain structure consisting of a cylindrical inner core with axial magnetization and a cylindrical outer shell with radial magnetization.The inner core leads to the appearance of a large Barkhausen jump at low axial fields. We have calculated the ratio M"/M, (the reduced remanence) as being of about 0.75 -0.80. Magnetic measurements performed on samples prepared by us confirm the existence of the large Barkhausen jump but with a reduced remanence of about 0.95 that suggests the existence of a supplementary axial tensile stress. The dependence of the reduced remanence on external tensile stresses for wires covered by glass and after the glass removal confirms the existence of the supplementary stress whose value was estimated as being of the order of 10 Pa.

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Amorphous magnetic glass-covered wires are of interest for basic research and potential applications. Their specific magnetic behavior originates in their very small diameters and in the high internal stresses induced during preparation. emoval of the glass cover leads to significant changes in their magnet~c ~r o p e r t~e s and behavior, thus improving their suitability for sensing applications. A thorough study of the changes produced by the glass removal implies the consideration of the changes produced in the internal stress distribution. We propose a method for the calculation of the residual internal stress distribution in wires obtained after the glass removal, based on the results of the magnetic measurements. The residual internal stress dis~r~bution allows us to explain the magnetic behavior o f these wires. We also present the advantages of wires obtained after the glass removal from the practical point of view in comparison with those of conventional amorphous wires.

We present a study of the evolution of the magnetic properties and behavior of Fe73.5Cu1Nb3Si13.5B9 glass covered wires and wires after glass removal with the annealing temperature up to 600 °C starting from the amorphous state. The changes induced in the magnetic properties of these wires are determined by the stress relief process occurring at temperatures below 550 °C, and by the appearance of the nanosized α-FeSi crystalline grains after annealing for 1 h at 550 °C. The nanocrystalline phase formation leads to an improvement of the soft magnetic properties of these wires—increase of permeability and decrease of the coercive force—but also determines the disappearance of the large Barkhausen effect presented by these wires in the amorphous state. Annealing at temperatures over 550 °C determines a depreciation of the soft magnetic properties of both glass covered wires and wires after glass removal. The magnetic behavior of such wires can be fully explained by taking into account the relaxation of the internal stresses with increasing the annealing temperature as well as the changes in the magnetostriction constant due to the appearance of the nanocrystalline grains.

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