Science Help

Magnetic Substances

Magnetic substance are the substances that can be permanently magnetized. These magnetic substances differ from other non-magnetic substances in the pattern of their dipoles. 

The non-magnetic substances have scattered dipoles whereas the magnetic substances have their dipoles aligned which makes it easier to magnetize them and they retain their magnetism even after the magnetizing field is removed.Categories of magnetic substancesThe magnetic substances fall into three categoriesThe ferromagnetic substances and the ferromagnetic substances: these are naturally occurring magnetic substances that are strongly attracted to magnets. 

The molecular structure of these substances helps them in retaining magnetism. Refrigerator magnets are made of Ferro magnets and magnetite and lodestone are ferri magnets. The difference between the ferri and Ferro magnetic substances is due to the oxygen content in the iron compoundsThe paramagnetic substances: These are also naturally occurring magnetic substances that not as strongly attracted to magnets as the Ferro and ferri magnetic substances are. 

These are much weaker magnetic substances and need sensitive instruments to detect the magnetic pull. Therefore these cannot be used for making permanent magnets. MagneticFerro fluids are an example of paramagnetic material.And the diamagnetic substances are even weaker than paramagnetic substances and are repelled by both poles of a magnet. The substances such as carbon, copper, water and plastic are all examples of diamagnetic substances. 

Superconductors are the best example of widely used diamagnetic substances; they repel any magnetic field from their structure.There are various other types of magnetic substances made for specific applications such as metamagnetism, superparamagnetism, spin glass, and super diamagnetism.Application of Magnetic substances:The magnetic substances are widely used in a number of items and machines that we use day in and day out. Examples are magnetic recording media, credit, debit or ATM cards, speakers, microphones, electric motors, generators, medicine, LCDs, toys, art, chucks, compasses, jewelry, magnetic levitation transport vehicles and in fail-safe devices.