Magnetic Properties of Matter

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Introduction to Magnetism

Magnetic forces mediate a subset of a physical phenomenon known as magnetism. The magnetism of matter is the force exerted by magnets when they attract or repulse each other. Magnetic moments and the electric currents of basic particles give rise to a magnetic field, which acts on other magnetic and currents moments. The magnetic state of a material based on pressure, temperature, and the applied magnetic field. As these variables shift, a substance can exhibit several forms of magnetism. Magnetic properties of matter can be found in various Earth materials that act as insulators and conductors of varying degrees and shapes.


Michael Faraday is the first statistician who was discovered classifying substances according to their magnetic properties in the 19th century. The strength of a magnetic field always decreases with distance, though the required mathematical relationship between strength and distance varies. 


Magnetic dipoles have been recognized, although some theories predict the existence of magnetic monopoles.

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Everyone Knows These Four Basic Facts About How Magnets Behave:

  1. A magnet has two endpoints called poles, one is called a north pole or also called a north-seeking pole, and the other is called a south pole or also called a south-seeking pole.

  2. The north pole of the first magnet attracts the south pole of a second magnet, while the north pole of the first magnet repels the second magnet's pole.

  3. A magnet creates a magnetic field and is an intangible sphere of magnetism all over it.

  4. The north pole of a magnet is roughly towards the Earth's north pole and vice-versa. That's because the Earth itself involves magnetic materials and behaves like a gigantic magnet.

Source of Magnetism

Magnetism is Derived from Two Sources:

  1. Electric current.

  2. Spin magnetic moments of elementary particles.

The magnetic properties of matter are mainly due to the magnetic moments of their atoms orbiting electrons. The magnetic moments of the nuclei of atoms are very small than the “electrons' magnetic” moments, so they are negligible in the condition of the magnetization of materials. 

In addition, even when the electron configuration is such that there are unpaired electrons and also non-filled subshells, it occurs frequently. In that case, the various electrons in the solid state will give the magnetic moments of that point in different, random directions so that the material will not be magnetic. Hence, the magnetic behaviour of a material is based on its structure, particularly its electron configuration, and also on the temperature. Depending on whether there is an attraction or repulsion between the north pole and south pole of a magnet, the matter is classified as being either paramagnetic or diamagnetic, respectively. 


Magnetic Properties of Matter

There are several magnetism properties of matters including Magnetization, Diamagnetism, Paramagnetism respectively.


Magnetization

In this section, we will learn about magnetization and the concept of magnetic intensity.

In electromagnetism, magnetization, also called magnetic polarization, is a vector field that contributes to the measure of the density of induced or permanent magnetic dipole moment in a given magnetic material. Magnetization is the magnetism of matter which was discovered by William Gilbert. The variation within this branch is described by direction and is either Axial or Diametric. As we know, magnetization results from magnetism, which results from the motion of electrons in the atoms or the spin of electrons in the atom or the nuclei. 


The theory of magnetization helps us in classifying the materials based on their magnetic properties. Net magnetization is the result of the response material to an external magnetic field. The magnetization of a sample material M is called the net magnetic moment for that material per unit volume. The mathematical formula of magnetization field or M-field is,

M = \[\frac{m_{net}}{V}\]

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In a magnetic field, paramagnetic materials have a weak induced magnetism, which disappears when the magnetic field is eliminated and Ferromagnetic and ferrimagnetic materials have strong magnetization. That can be magnetised to retain its magnetism in the absence of an external field, resulting in the creation of a permanent magnet.


Diamagnetism

Michael Faraday discovered diamagnetism in September 1845. This is the weak form of magnetism that is arranged in the presence of an external magnetic field. This generates a magnetic moment that is very small and in a direction opposite to that of the applied field. Diamagnetic is a magnetism of matter in which materials are opposed by a magnetic field, an applied magnetic field creates an induced magnetic field in them that is usually in the opposite direction, causing a repulsive force. In addition, paramagnetic and ferromagnetic materials are attracted by a magnetic field. 


When placed inside the strong diamagnetic and electromagnetic materials are attracted toward regions where the magnetic field is weak.  In ferromagnetic and paramagnetic material, the weak diamagnetic force is controlled by the attractive force of magnetic dipoles in the material. 

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Diamagnetism was first discovered by Michael Faraday in the year of 1845. In addition, when Anton Brugmans observed in 1778 that bismuth was opposed by magnetic fields. A simple rule of thumb is used in chemistry to determine whether a particle or atom or iron is paramagnetic or diamagnetic materials. In diamagnetic material, all electrons in the atom are paired, and the substance made from this atom. A paramagnetic material has an unpaired electron.


Paramagnetism

Paramagnetism has an unpaired electron in the material, so most atoms are incompletely filled with atomic orbitals. Hence this atom is called paramagnetism. Paramagnetism is a form of magnetism whereby several materials are weakly attracted by a strong magnetic field. In addition, paramagnetism creates a magnetic field in the direction of the applied magnetic field. Paramagnetism was discovered by the British scientist Michael Faraday in 1845. The materials that are arranged in paramagnetism are called paramagnetic. Therefore, true paramagnets are arranged in magnetic susceptibility conforming to the Curie-Weiss laws and exhibit paramagnetism over a wide temperature range. 


This type of magnetization depends on Curie’s law. According to Curie’s law, paramagnetic materials, magnetic susceptibility χ are inversely proportional to their temperature. It is represented as;

M = χH = C/T x H

Where,

M = magnetization,

χ = magnetic susceptibility,

C = material-specific Curie constant,

T = absolute (Kelvin) temperature,

H = auxiliary magnetic field.

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Here are some examples of paramagnetic materials, aluminium, oxygen, titanium, and iron oxide (FeO). In addition, a simple rule of thumb is used in chemistry to determine whether a particle or atom or molecule is paramagnetic or diamagnetic. This rule depends on the paired or unpaired electron.

FAQs (Frequently Asked Questions)

1. Is Magnetism a Force?

Answer: Magnetism is one angle of the combined electromagnetic force. The physical phenomena begin from the force caused by magnets, objects that can produce fields that repel or attract another object. A magnetic field applying force on particles in the magnetic field is due to the Lorentz force. The force reacts on an electrically charged particle in a magnetic field. It depends on the magnitude of the charge and the velocity of the particle, and the strength of the magnetic field.

2. Why is Magnetism a Physical Property? 

Answer: Magnetism is a physical property because if any object attracts a magnet then it does not change the substance it (changes the composition) itself and doesn't involve chemical reactions. Here are some examples of physical properties: smell, boiling point,  colour, melting point, freezing point, infra-red spectrum, attraction (paramagnetic) or repulsion (diamagnetic) to magnets.

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