Diamagnetic materials

Diamagnetic materials are those in which the individual atoms or molecules or ions do not possess any net magnet moment of their own.

When a sample of a diamagnetic material is placed in an external magnetic field of induction (B), a small magnetic moment is produced in each atom or molecule or ion proportional to B, but pointing in the opposite direction.

In other words, those materials which when placed in a magnetic field become weakly magnetized in a direction opposite to that of the applied field, are called as diamagnetic materials.

Example: bismuth, antimony, copper, gold, quartz, mercury etc.

Reference: This article is referred from my book “electrical engineering materials” having ISBN 978-81-272-5069-0. In case of any doubt, you can put your question in the comment section.

Relative magnetic permeability

Relative magnetic permeability is defined as the ratio of permeability of medium (μ) to the permeability of free space (μ0)

μr = μ/μ0

or                                 μr = B/H/(B0/H)

or                                 μr = B / B0

is permeability of free space.

Magnetic permeability

Magnetic permeability is defined as the degree to which the magnetic lines of force can penetrate or permeate the material. It can also be defined as the ability of the material to permit the passage of magnetic lines of force through it.

As the magnetic induction is proportional to the magnetising field

B proportional H

or                     B = μH

where μ is called the permeability of the medium (material)

Reference: This article is referred from my book “electrical engineering materials” having ISBN: 978-81-272-5069-0.

Intensity of magnetisation

It represents the extent to which a specimen is magnetised when placed in a magnetising field.

Or in other words the  intensity of magnetisation of a magnetic material is defined as the magnetic moment per unit volume of the material.

                                    M = Magnetic moment/volume = μM / V                            …1

Let       a = Uniform area of cross-section of the magnetised specimen.

            l = magnetic length of the specimen.

            m = strength of each pole of the specimen,

As                    μm = ml

and                   V = al

then equation (1) becomes

            M = m x 2l / a x 2l

or         M = m/a

thus intensity of magnetisation of  a  magnetic material is also defined as the pole strength per unit area of cross-section of the material.

Unit :    M= magnetic moment / Volume

            M= Amp.metre2 / metre3 = Am -1

These are S.I unit of M

Reference: This article is referred from my book “electrical engineering materials” having ISBN: 978-81-272-5069-0.

If you want to purchase winnerscience books, then please see “Winnerscience Books” page on top of website.

Magnetic Intensity

Magnetic intensity is same as magnetizing force.

Therefore, it is also defined as the degree to which a magnetic field can magnetise a material is expressed in terms of magnetizing force.

Consider a toroidal solenoid with n turns per unit length carrying a current I. The magnetic induction of the field produced will be Continue reading “Magnetic Intensity”