Theory of the remanence in grain-oriented Si-Fe sheets in presence of external stresses

The decrease of remanence and permeability is stressed grain-oriented 3% Si-Fe laminations with high texture perfection is related to the presence of transverse closure domains progressively collapsing with increasing applied stress. Closure domains appearing both at grain boundaries and at Epstein frame joints are responsible for the decrease of remanence and permeability in the low stress region (σ<5 MPa). A further decrease in the high stress region (σ>5 MPa) is related to the collapse of closure domain spikes. These spike structures strongly influence the law of approach to saturation and the magnetostriction of g.o. Si-Fe laminations in the high field region H«Hc. It is shown here that also the low field (O<H≲Hc) properties of Si-Fe laminations in presence of a tensile stress are explained in terms of the collapse of the same transver se closure domains.