Types of magnetism

☆ Diamagnetism
☆ Paramagnetsim
☆ Feromagnetsim
☆ Antiferromagnetsim

■ Diamagnetsim

• Diamagnetsim is a fundamental property of all matter, although it is usually very week. It is due to non co-operative behaviour of obtaining electrons when exposed to an applied magnetic field . Diamagnetic substance are compund of atoms which have no net magnetic moment . however when exposed to a filed .If we plot M vs H we see

■ Paramagnetism

• This class of material some of the atoms are ions in the material have a net magnetic moment due to unpaired electron in partially filled orbit . Once of the most important atoms with unpaired electrons in iron . However the individual magnetic moment do not interact magnetically, and like diamagnetism , the magnetization is zero when the field is removed . In the presence of the field there is now a partial alignment of the atomic magnetic moment in the direction of the filed resulting in a net positive magnetism and positive susceptibility

■ Ferromagnetism

When tou think magnetic materials, you probably think iron nickel or magnetic . Unlike paramagnetic materials, the atomic.moment is that materials exhibit very strong interactions. These interaction produce by electronic exchange force and result in a parallel or anti parallel alignment of atomic moment . Exchange fore are very large equivalent to a filed on the order of 1000Tesla or approximately a 100million times the strength of the earth field.

■ Antiferromagnetism
• The material moment of atoms or molecules usually to the spin of electron align in a regular pattern with neighbouring spins pointing in opposite direction . This is like ferromagnetism ,a manifestation of ordered magnetsim . Generally antiferromagnetic order may exist at sufficiently low temperature ., vanishing at and above a certain temp.The tempreature above the Neel temperature the material is typically paramagnetic.

☆Applications

•  Eletro motor ange generator
•  Magnetic storage
• Magnetic bearing
• Magnetic separator
• Medical appliance
• Magnetic Resonance Imaging MRI
• For security purpose
•Eddy current brake