Magnetic Susceptibility

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Susceptibility in Physics

Magnetic susceptibility is a proportionality constant. It has no dimension. The term is associated with many things in Physics.

Susceptibility meaning in physics signifies the total amount of magnetization of material at the same time when a magnetic field is applied. This phenomenon is due to the interactions of electrons and nuclei. 

It happens when both the nuclei and the electrons are applied externally under the magnetic field. The magnetic susceptibility is nothing but the total amount of magnetization of a material when it undergoes a magnetic field. 

This article is all about susceptibility Physics and other stuff associated with susceptibility.


Susceptibility of Magnetic Material

From the introduction, you can gain basic ideas about magnetic susceptibility meaning. Magnetic susceptibility helps in the measurement of the amount of magnetization when it comes under the applied magnetic field.

Do you know the value of magnetic susceptibility?

The formula that can be helpful for the calculation of magnetic susceptibility values is:

χ = M/H

Here,

  • χ = Magnetic susceptibility

  • H = field intensity

  • M = magnetization

Various Types of Magnets

1. Paramagnetic Material 

Paramagnetic materials are the type of objects (Magnetic materials) that lies within (align with) the magnetic field. The value of Magnetic susceptibility is χ > 0 in the case of paramagnetic materials. This expression has some sort of expression. 

When you try to determine the values for paramagnetic materials, they always give you a small positive value. 

Paramagnetic materials are having different dependencies. The temperature of each paramagnetic material is a dependent quantity. The rise of temperature in paramagnetic materials can lessen the magnetic field. 

These types of materials have relative permeability that varies from 1.00001 to 1.003. A few examples of paramagnetic materials are given below: 

  • Alkaline earth metal

  • Aluminum

  • Oxygen 

Curie’s law is available to calculate the magnetization of the paramagnetic materials. So, the magnetization formula according to Curie’s law can be written as:

M = χ H = {C / T x H}

Where,

  • M = magnetization

  • C = material-specific Curie constant

  • χ = magnetic susceptibility

  • H = auxiliary magnetic field

  • T = absolute (Kelvin) temperature

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2. Diamagnetic Material

Diamagnetic materials are the types of Magnetic materials that line up alongside the magnetic field. The value of magnetic susceptibility for diamagnetic materials is χ<0. The relation signifies that for diamagnetic material, the value of magnetic susceptibility is always a negative one. 

The magnets do not attract these materials but prefer to repel. The magnetic field of the diamagnetic material travels from a stronger field to a weaker field. Diamagnetic materials are not dependent on temperature. 

Diamagnetic materials have magnetization that acts in the opposite direction. magnetization intensity of the diamagnetic materials lies within a definite value. Relative permeability does not vary at all for every Diamagnetic material. Examples of Diamagnetic materials are: 

  • Gold 

  • Tin 

  • Mercury 

  • Water 

  • Copper 

  • Zinc 

  • Bismuth 

  • Silver 

  • Antimony

  • Marble 

  • Glass 

  • NaCl, etc.

Here is the table for Diamagnetic Materials and the value of their volume susceptibility:


Material

χv  [× 10−5 (SI units)]

Superconductor

−105

Pyrolytic carbon

−40.9

Bismuth

−16.6

Mercury

−2.9

Silver

−2.6

Carbon (diamond)

−2.1

Lead

−1.8

Carbon (graphite)

−1.6

Copper

−1.0

Water

−0.91


3. Ferromagnetic Material

Ferromagnetic materials are the types of magnets that can possess higher magnetization when present in a magnetic field. The attraction force of the magnets for the ferromagnetic materials is very high. The magnetic field of the ferromagnetic materials always come from weaker fields to stronger fields. 

You won’t find any constant relative permeability for ferromagnetic materials.  The value of relative permeability varies from 1,000 to 1,00,000. You also find a very high and positive magnetic susceptibility among ferromagnetic materials.

The magnetic susceptibility Physics relies on the applied field. A few examples of ferromagnetic materials are 

  • Iron 

  • Cobalt 

  • Nickel (and their alloys)

Interesting Facts on Magnetic susceptibility

The magnetic susceptibility can indicate the behavior of a material. It can elaborate whether a material can get attracted or repelled out within the magnetic field. Paramagnetic materials can be attracted by the magnetic field when they find the regions that have greater magnetic fields. This happens when they align with the applied magnetic field. 

In different scenarios, you may find some unusual behavior with the diamagnetic materials. These types of materials do not support the alignment of magnetic fields. As a result of which, each material gets a push-away towards the regions of lower magnetic fields. 

The magnetization of the material is always on the top of the applied field. It is added to its original magnetic field. It can create different types of field lines to manipulate under paramagnetism or get the exclusion for diamagnetism.

Magnetic susceptibility values can have some sort of Quantitative measures. All of them can give us the proper insights that are based on the structure of materials. Also, it can provide insight into energy levels and the bonding of the materials. 

FAQs (Frequently Asked Questions)

Q1. How Do You Define Retentivity?

Ans: Retentivity is the quality of a material that can offer some resistance or retain magnetization. This value is significantly calculated as the measurement of magnetic field strength. You can find out the actual value after the elimination of an inducing force.

Q2. Why Do the Manufacturers Prefer Soft Iron for the Making of Electromagnets?

Ans: Electromagnets are manufactured with soft iron because soft iron has a higher susceptibility and lower retentivity. It is the only material that can give the industrialists hope for better product development.

Q3. What Factors Depend on the Strength of the Magnetic Field?

Ans: When you arrange a certain number of coils that comes under the magnetic field, then the following factors can influence the strength of the magnetic field:

  • The total amount of current present inside the coil

  • Number of turns of the coil

  • The core material of the coil

Q4. How Do You Explain the Term “Coercivity”?

Ans: Coercivity is the nature of the materials that is useful to find out the optimal (minimum) value of the magnetizing intensity requisite for the material to bring it into the original form. When material comes under the magnetizing field, coercivity can be helpful to bring it back into its normal state.

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