Permanent magnets can be natural products, also known as lodestone, and man-made one with neodymium iron boron as the famous representative which have strong magnetic field.
After being heated to a certain temperature, the magnetism of Non-permanent magnets would suddenly disappear. During this process, all magnet molecules in magnets are changed from ordered to unordered. If put the magnets which have lost magnetism into magnetic field, when the magnetization strength reaches a certain value, they would have magnetism again. magnet molecules are changed from unordered to ordered.
Man-made magnets can be divided into horseshoe magnet and bar magnet, both of which are so common in our daily life. Compared with bar magnet, horseshoe magnets are more popular. What single side magnet is that one side has magnetism while the other side only has weaker magnetism. How to change common magnets into single side magnet? It is so simple, just put galvanized iron deal with special ways on one side of the common magnet, the magnetism on this side would be shielded while on the other side the magnetism would become stronger. In many cases, single side magnets are needed because it can reduce costing and economize magnetic materials.
Diamagnetic materials are some types of anti-magnetic materials. When putting them in the magnetic field, they have produced a weak repulsive force to the magnetic force.
Paramagnetic refers to a material's magnetic state. Some materials may be influenced by the external magnetic fields to produce the same direction quantity of magnetism. Such material has a positive magnetic susceptibility. The opposite conception to paramagnetic is anti-magnetic.
Electromagnet which belongs to the Non-permanent magnet is the device that can generate magnetic force through passing electric current. It is an essential tool in modern society where are full of electric power.
Superconducting magnet is the man-made magnet that made of superconducting material such as superconducting coil.
When some conductor is in special temperature, its electric resistance would turn into zero. The two important characters of superconductor are zero electric resistance and diamagnetism. The temperature when the electric resistance of superconductor becomes zero is named as the superconducting critical temperature.
The chemical formula of Neodymium magnet is Nd2Fe14B and it is a man-made permanent magnets. Up to now, it is the permanent magnets which have the strongest magnetic force. Because of its strong magnetic force, nowadays Neodymium magnets are widely used in electronic products such as hard drives, mobile phones, earphones and so on.