There rotation the single domain with the reversed field

B	Field removal or reversal	18.7 Domains and Hysteresis


		forward and reverse saturations (points S and
		S�). The hysteresis loop is represented by the
Initial magnetization		solid curve; the dashed curve indicates the
Initial magnetization
0	+Hc

oriented with the H field. Alteration of the domain structure with magnetic field for an iron single crystal is shown in the chapter-opening photograph for this chapter.

From saturation, point S in Figure 18.14, as the H field is reduced by reversal of field direction, the curve does not retrace its original path. A hysteresis effect is produced in which the B field lags behind the applied H field, or decreases at a lower rate. At zero H field (point R on the curve), there exists a residual B field that is called the remanence, or remanent flux density, Br; the material remains magnetized in the absence of an external H field.

S-280	●	Chapter 18 / Magnetic Properties	N	L
		B
		M
		M			saturation is indicated by curve LM.

B	Hard	FIGURE 18.16 Schematic magnetization



		permission of John Wiley & Sons, Inc.)

Soft