3-D Branching of Magnetic Domains on Compressed Si-Fe Steel With Goss Texture

The influence of an applied compressive stress on the hysteresis curve and domain structure in conventional (110) [001] Fe-3%Si steel cut parallel to the rolling direction was studied. Quasi-static hysteresis loops under compressive stress up to 70 MPa were measured. The magnetic domains and magnetization processes were observed by longitudinal Kerr microscopy at different levels of stress. With increasing compressive stress, the domain structure in the demagnetized state evolves from initial simple 180° slab-like domains along the surface-parallel easy axis into stress pattern I, checkerboard pattern, and finally into stress pattern II at high stresses. The checkerboard pattern, observed at the intermediate stress level between 10 and 25 MPa, has not been reported before such thin sheets. The applied magnetic field makes the surface-parallel [001] domains with magnetization in field direction grow into the bulk at the expense of all other domains for all stress levels. The magnetization curves at stress above 10 MPa have a constricted shape with a sudden change of magnetization at a critical fields. The averaged critical field changes linearly with stress with a slope close to theoretical predictions.