A Simple Domain Structure in an Iron Crystal Showing a Direct Correlation with the Magnetization

A hollow rectangle cut from a single crystal of 3. 8 percent silicon iron has been studied with the aid of powder patterns and flux measurements. The edges and surfaces were all cut accurately parallel to 100>, the directions of easy magnetization. The domain pattern consists of 8 domains, four forming an inner rectangle magnetized in one direction and the others forming an oppositely magnetized outer rectangle. Changes in magnetization occur by the growth of one set of domains at the expense of the other. In the saturated condition, each leg of the rectangle is one domain about 1. 50. 10. 1 cm in size. Implications of these results in connection with Barkhausen effect are discussed, and a method of measuring the energy of the Bloch wall is proposed.