The core of an electromagnet is typically made of soft iron. Soft iron is used because it can be easily magnetized and demagnetized, has low carbon content, large magnetic susceptibility, small retentivity, and does not retain magnetism when the current is switched off. This makes the electromagnet a temporary magnet, where the core's magnetic domains align with the magnetic field created by the coil and enhance the field strength significantly, but lose their magnetism when current stops.
Key Points About Electromagnet Core
- The core material is usually soft iron or another ferromagnetic material with high magnetic permeability.
- Soft iron concentrates and guides the magnetic field created by the coil, increasing the magnet's strength by hundreds or thousands of times.
- The core being soft iron means it loses its magnetism quickly when the electric current is turned off, allowing the electromagnet to be controlled easily.
- The core’s magnetic domains align with the coil’s magnetic field, reinforcing the overall magnetic field.
Why Soft Iron?
- Easy magnetization and demagnetization.
- Large susceptibility and small retentivity.
- Temporary magnetism, suitable for electromagnets.
- Low corrosiveness compared to steel.
This makes soft iron an ideal choice for the core of electromagnets in applications like electric bells, motors, transformers, and lifting magnets.