Magnetization Effects in Matter

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A sample of copper is magnetically drawn to the low field area to the right in the drawing, regardless of the orientation of the magnetic field. Diamagnetism is the name given to this type of behaviour.

A piece of aluminium, on the other hand, is drawn to the high field area by a phenomenon known as paramagnetism. Due to magnetization effects in matter, a dipole moment is created when the matter is subjected to an external field. Hence the degree of induced magnetization effects in matter is given by the magnetic susceptibility of the material χm, which is commonly defined by the equation

M = XmH

The magnetic field H is called the magnetic intensity, like M, is measured in units of amperes per metre and Xm is denoted as the degree of induced magnetization.

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For copper, the created dipole is opposite to the direction of the external field. Magnetic permeability is often used for ferromagnetic materials such as iron that have the largest magnetic susceptibility dependent on the magnetic field and the previous magnetic state of the sample. The magnetic permeability is defined by the equation,

B = μH.

The terms which are based on magnetization effects in matter are discussed in detail below.

Magnetic Field

A magnetic field is a vector field in the part of a magnetic material, electric current, or changing electric field, in which magnetic force is observable. Moving electric charges and intrinsic magnetic moments of elementary particles linked with a fundamental quantum property known as the spin create a magnetic field. The magnetic fields and electric fields are directly connected and are elements of the electromagnetic force, one of nature has four fundamental forces. A moving charge in a magnetic field has experienced a force perpendicular to its velocity and the magnetic field. The magnetic field of a permanent magnet draws or repels other magnets, as well as ferromagnetic materials such as iron.

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A magnetic field surrounded by magnetized materials and is created by electric currents such as those used in electromagnetic fields, and by electric fields varying in time. 

A sample of copper is magnetically drawn to the low field area to the right in the drawing, regardless of the direction of the magnetic field. Hence is termed diamagnetism. A sample of aluminium is attracted toward the high field region is called paramagnetism.

A magnetic dipole is created when the matter is subjected to an external field. 

Magnetic Dipole

A dipole of an object generates a magnetic field in which the field is considered to emerge from two opposite poles, one is the north pole and the second is the south pole of a magnet, much as an electric field emerge from a positive charge and a negative charge in an electric dipole. 

The energy of a magnetic dipole is called the magnetic dipole moment. The amplitude of a uniform magnetic field is equal to the maximum amount of torque on the magnetic dipole, which happens while the dipole is at right angles to the field.

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The magnetic dipole has a measurement of current times or energy divided by magnetic flux density. The magnetization M of a small volume of matter is the addition of the magnetic dipole in the small volume divided by that volume. 

Magnetic Flux

In physics, specifically magnetism, the magnetic flux is defined as the number of magnetic field lines passing through a given surface and magnetic field B over that surface. Hence, the area under consideration of any size and any orientation concerns the direction of the magnetic field. Magnetic flux is usually denoted by Φ or ΦB. The magnetic flux symbol is Φ or ΦB.

Magnetic flux formula is given by:

ϕB = B.A = BAcosθ


  • ΦB is the magnetic flux.

  • B is the magnetic field

  • A is the area

  • θ is the angle at which field lines cross the surface area

Magnetic flux is generally calculators with a flux meter. The SI unit and CGS unit of magnetic flux is given below:

  • The SI unit is Weber (Wb).

  • The CGS unit is Maxwell.

Magnetic Intensity

The magnetic field to magnetization ratio of a material medium is called its magnetic intensity (H). Magnetic intensity of magnitude is calculated by the number of ampere-turns that flows around the unit length of a solenoid, required to produce that magnetic field.

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Therefore, the magnetic intensity, due to a solenoid of n turns per meter length be H = ni, 


i is the current

n = N/l, N is the total number of turns and l the size of the solenoid. 

Hence, the magnetic intensity does not depend upon the nature of the medium.

The SI unit of magnetic intensity (H) is ampere-turns per meter (Am⁻¹).

Magnetic Permeability

Magnetic permeability is described as the property of the material to accept the magnetic line of force to pass through it. In other words, the magnetic material can support the occurrence of the magnetic field. In (H) magnetic permeability of the magnetic line of force is directly proportional to the conductivity of the material. Magnetic permeability is the proportion of a material to respond to how much electromagnetic flux it can support to pass through itself within an applied electromagnetic field. In addition, the magnetic permeability of a material is the degree of magnetization capability.

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Magnetic permeability is denoted by μ which is a Greek Letter. In 1885, Mathematician scientist Oliver Heaviside had termed magnetization effects as μ.

The SI unit is Henry per meter or newton per ampere-square.

FAQs (Frequently Asked Questions)

1. How Does Magnetism Affect the Environment?

Answer:  A much cooler effect is that the Earth's magnetic field acts as a shield for us. Everyone can see, besides the light, the sun is constantly spitting out charged subatomic particles. These subatomic particles are constantly streaming towards the Earth, and without any magnetic field, they will penetrate our atmosphere, potentially causing significant harm to the atmosphere, surface life, and electrical devices. 

2. What are the Effects of Magnets on Metals?

Answer: Magnets are objects, which can attract some metals, like iron and steel. When you rub a piece of steel with a solid magnet, the steel becomes a magnet as well. Magnets do not attract such metals, like copper or gold. Two magnets also attract each other, but only if they face in opposite directions. A magnet has two ends called poles, the first is the north pole and the second is the south pole.

3. Can You Create a Magnetic Field?

Answer: It is impossible to generate magnetic waves without the presence of magnets or an electric field. Electric fields are generated by electric charges. For instance, if you charge a balloon statically by pressing it against your scalp, the balloon generates an electric field. Magnetic fields are always created by magnets.

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