  Recent measurements of the magnetoimpedance (at a fixed frequency of 1 MHz)
of cobalt-rich wires subjected to torsion stress show an asymmetry as a
function of torsion angle stemming from residual anisotropies induced during
wire fabrication. We interpret these measurements with a simple model based on
the competition between a circumferential magnetic anisotropy and another one
induced by torsional and residual stress. This allows extraction of the
physical parameters of the wire and explains the positive and negative torsion
cases. The agreement between theoretical and experimental results provides a
firm support for the model describing the behaviour of the anisotropy field
versus static magnetic field for all torsion angles.
