Question

Mention the desired properties of magnetic materials used in making electromagnets.

Answer 1

Magnetic permeability is defined as the proportion of magnetic induction to the magnetic intensity. It is a scalar measure. The materials suitable for forming electromagnets should have low retentivity and low coercivity. Soft magnets can hold their magnetization as large as the external magnetic field departures, i.e., low retentivity. They also possess a low coercivity, i.e., their retained magnetization can be eliminated very quickly.

Complete step-by-step solution:
Magnetic permeability, also indicated as permeability in electromagnetism, is a magnetic material property that supports the formation of a magnetic field. Magnetic permeability is a quality that allows magnetic lines of force to move through a material. In different words, the magnetic permeability of a substance can also be assumed to be its magnetization capacity. This helps in resolving how much magnetic flux the substance can support, which will cross through it. Magnetic permeability helps us estimate a material's resistance to the magnetic field or measure how a magnetic field can enter through a material. If the material has higher magnetic permeability, higher will be the conductivity for magnetic lines.
The retentivity of a substance is its ability to persist magnetized after the external magnetizing field has terminated to exist. A substance with high retentivity will hold some magnetic properties; it will convert a permanent magnet, whereas a substance with low or no retentivity will not keep the magnetic properties; it will miss its magnetization.
The coercivity is the intensity of the implemented magnetic field needed to decrease the magnetization of that material to nothing after the sample's magnetization has been sent to saturation.
Coercivity is usually estimated in oersted or ampere/meter units. When the coercive field is excellent, the material is said to be a complex or permanent magnet. A magnet with a low coercive field is an electromagnet (soft) and may be used in microwave devices, transformers, magnetic shielding, or recording heads.
These materials are being utilized to make electromagnet an electromagnetic material with high permeability, low retentivity and low coercivity. Soft iron is a proper material as a soft ferromagnet.

Note: Soft materials can be quickly magnetized and demagnetized. Permeability also depends on various factors such as the material's nature, humidity, medium position, temperature, and frequency of the dynamic force. Magnetic permeability is constantly positive and can change among a magnetic field.