Magnetization changes induced by stress in a constant applied field

Measurements have been made of magnetization curves obtained by applying stresses to various polycrystalline magnetic materials in the presence of a small, constant, magnetic field. The materials examined were nickel, mild steel, and both isotropic and cube textured silicon iron. Residual stray fields were carefully compensated. Both compressive and tensile stresses were applied in the range 0 to 10 kg mm⁻². The curves are compared with the theory proposed by Brown in 1949, in which the stress is replaced by an equivalent field, which has been found to be valid at the smaller stresses. There are many features which cannot be reconciled with Brown's analysis, in particular the difference between tension and compression. A tentative explanation is put forward based on discontinuous changes in domain structure.