V S Severikov’s research while affiliated with Petrozavodsk State University and other places

We present and compare results of measurement of saturation magnetostriction constants of amorphous ribbons Fe 80- x Co x P 14 B 6 ( x = 23, 25, 28, 32, 40 at.%) and the reference Fe 40 Ni 40 P 14 B 6 specimen employing Narita and Becker-Kersten methods. We also modified a strain gauge-based method to enable measurements of complete magnetic field dependence of magnetostriction coefficients.

We evaluate properties of the prototype of a strain gauge capable to discriminate different strain components: tension and torsion. It makes use of magnetoelastic effect in new Fe48Co32P14B6 metallic glass. As a sensing material, it surpasses characteristics of commercial Iron-Nickel Metglas® alloy: relative differential permeability of as quenched amorphous ribbon is of about 110000, the saturation induction Bs = 1.45 T, coercive field as low as 4 A/m, Curie temperature above 700 K, and significantly higher thermal stability. Different deformation components were determined through the analyses of the shape of hysteresis B-H loops. Fe-Co-P-B glass strain gauge can simultaneously detect as small tensile strains as 1.9 × 10⁻⁵ and less than 0.13 deg/cm of torsional distortions.

Becker-Kersten method, which involves observing hysteresis M-H loops under mechanical stress, was applied to measure magnetostriction properties in amorphous rapid quenched ribbons Fe80-x Cox P14B6. It is shown that magnetostriction constant increases with the growth of cobalt atomic content from (1.75 ± 0.13)×10⁻⁶ for x = 25 to (1.60 ± 0.05)×10⁻⁵ for x = 40.

The paper presents the possibility to build a tension gauge capable to discriminate different kinds of deformations: compression and twisting (induced by torsion strain) based on the magnetoelastic effect in new metallic glasses Fe80−x Cox P14B6. Applied loads increase coercive field H c, saturation induction B s and rectangularity of magnetic hysteresis loop. For example, hysteresis loop traced for 1 mm narrow, 50 cm long and 30 μm thick Fe40Co40P14B6 straight ribbon subjected to longitudinal stress of 346 MPa shown increased B s from 1.24 to 1.7 T and squareness from 0.55 to 0.88 compared to unloaded specimen. For twisting, on the contrary, both squareness and coercive field vary whereas the value of B s remains unchanged.