.soft iron

Soft iron is iron that is easily magnetized and demagnetized with a small change of magnetic field. Soft iron does not refer to the soft nature of the metal; in fact, soft iron is also a hard, metallic iron. But unlike in hard iron, the magnetic domains shifted towards the direction of a magnetic field can be shifted back to the initial state. In other words, it is reversible. But the returned magnetic domains will align in a random manner.

Figure 2: An Electromagnet

Soft iron is used in the production of electromagnets. Therefore, the field can be turned on and off. An electromagnet can be made by coiling a wire around a piece of soft iron and connecting the two ends of the wire to a battery. When the current is running through the wire, this system acts as a magnet. Then the domains of the soft iron bar align with the direction of the applied field and, the intensity of the magnetic field is increased by several magnifications.