Definition
Temporary magnets are magnets that retain their magnetism in the presence of an electric current or a permanent magnetic field. #PhysicsDefinitions
Definition
Permanent magnets do not require the presence of an electric current or a permanent magnetic field to retain their magnetism #PhysicsDefinitions
- magnets are temp / perm → depending on material they are made of
Soft and Hard Magnetic Materials
- 2 types of ferromagnetic materials → such as soft and hard magnetic materials
terms “soft” and “hard” → do not refer to hardness of material
- refer to the materials ability to become magnetised and remain magnetised
| Magnetic Material | Soft | Hard |
|---|---|---|
| Example | Soft Iron | Steel (alloy of iron) |
| Properties | Easily magnetised and demagnetised | difficult to magnetise and demagnetise |
| Common Uses | temporary magnets like electromagnets in junkyards | permanent magnets such as magnetic recording media in hard disk drives. |
Soft magnetic materials → have stronger induced magnetism compared to hard magnetic materials.
Experiment that describes this:
Magnetic Materials:
- iron
- nickel
- cobalt
- rare earth metals (notably samarium and neodymium)
- best magnets are alloys (mixtures) of these elements.
Non-Magnetic Materials
- copper
- gold
- silver
- aluminium
- most non metals are non magnetic