Permanent vs Temporary Magnets
Magnets are very special objects in our daily lives. The electricity we use is generated using magnets. Navigations were done using magnets; equipment such as hard drives, audio cassettes and floppy discs are based on magnetism. The theory of magnetism is very important in the field of physics. It is vital to have a very good understanding in the concept of magnetism in order to excel in fields such as electromagnetic field theory and all related fields. In this article, we are going to discuss what magnetism is, what permanent magnets and temporary magnets are, their applications, the similarities of permanent magnets and temporary magnets, and finally the difference between permanent magnets and temporary magnets.
In order to understand permanent magnetism, one must first understand the concept of magnetism and magnetic materials. Magnetic induction is the process of magnetization of materials in an external magnetic field. Materials can be categorized to several categories according to their magnetic properties. Paramagnetic materials, Diamagnetic materials and Ferromagnetic materials are to name a few. There are also some lesser common types such as anti-ferromagnetic materials and ferrimagnetic materials. Ferromagnetic materials are also paramagnetic materials with zones of magnetic dipoles in one direction even prior to the external magnetic field is applied. Hard magnetic materials have more powerful magnetization than the soft magnetic materials when exposed to an external field. Hard magnetic materials will contain the magnetism even after the external field is removed. These are used to create permanent magnets. When the external field is applied, these magnetic zones will align themselves parallel to the field so that they would make the field stronger. Ferromagnetism is left in the material even after the external field is removed, but paramagnetism and diamagnetism vanishes as soon as the external field is removed.
Temporary magnets are materials that behave as magnets only when an external magnetic field is present. Such materials are also known as soft magnetic materials. The magnetic properties of the material disappear as soon as the external magnetic field is removed. These magnets act as flux transferring mechanisms. If a current carrying coil is wound around a soft magnetic material, the magnetic field will be several times larger than the original magnetic field. The soft magnetic materials are a part of the ferromagnetic material family. The soft magnetic materials show strong magnetic properties in an external magnetic field but lose the magnetism after the external field is removed. This causes a leaf like hysteresis curve.
What is the difference between Permanent Magnet and Temporary Magnet?
• Permanent magnets have the magnetic properties even if the external field is zero. Temporary magnets have magnetic properties only in the presence of an external magnetic field.
• Permanent magnetism is seen on hard magnetic materials, which fall in to the ferromagnetic material family. Temporary magnetism is seen in soft magnetic materials, paramagnetic materials and diamagnetic materials.
• Permanent magnets are used in devices such as electric motors and generators. Temporary magnets are used in places such as cranes.