Stray fields at grain boundaries in demagnetized stress coated HI-B sheets

In this paper, a first attempt to measure stray fields existing at grain boundaries in demagnetized HI-B sheets is reported. The spatial variation of these fields as function of tensile stress applied in the rolling direction was recorded by means of a micro Hall plate in connection with a computer-controlled scanning system. A simple model for the stray field generation at grain boundaries is presented for the interpretation of the results. It was found that specific supplementary domain structures do not exist directly at the grain boundaries in the type of material investigated here. Instead, tree-like structures appearing along the main domain walls are assumed to reduce stray fields at boundaries in the unstressed state. In the stressed state, these domains were found to disappear, and spike domains were spontaneously formed taking over their function.