When considering the circular motion of electrons, the genesis of magnetism can be explained. Inside the atoms, electrons move in circular orbits around the nucleus, analogous to a circular coil conveying current. The orbital magnetic moment is created by the electron’s orbital motion. A spin magnetic moment is created when electrons spin about in their own axis. The vector sum of the orbital and spin magnetic moments gives the magnetic moment of an atom. Magnetic compounds are categorised into three classes based on their magnetic properties: diamagnetic, ferromagnetic, and paramagnetic.

Definition of Diamagnetic

When diamagnetic materials are exposed to an external magnetic field they become weakly magnetised in the opposite direction as the applied field. Diamagnetism describes the sort of magnetism exhibited by certain materials. Copper, gold, antimony, bismuth, silver, lead, silicon, mercury, and other diamagnetic materials are examples. An orbital magnetic moment is created by the electron’s orbital motion. Furthermore, electrons have a tendency to spin around their own axis, resulting in a spin magnetic moment. An atom’s electrons can spin either clockwise or counter clockwise. Electrons can also rotate around the nucleus in a clockwise or counter clockwise orientation.

The magnetic moments of atoms and orbital magnetic moments have been arranged in diamagnetic substances in such a way that the vector sum of an atom’s magnetic moment becomes zero.

Characteristics

• The magnetic moment of each atom in a diamagnetic substance is calculated to be zero.
• They can be repelled by a weak magnetic field.
• When diamagnetic substances are placed in a non-uniform magnetic field, they shift from the stronger to the weaker side of the field.
• When these materials are exposed to an external magnetic field, they become weakly magnetised in the opposite direction as the field. In diamagnetic materials, magnetic susceptibility is shown to be negative.

Ferromagnetic Substance

Ferromagnetic substances are those that get strongly magnetised in an external magnetic field in the same direction as the applied field. Even after the magnetic field is removed, these substances retain their magnetic moment. Ferromagnetic materials gravitate from weaker to stronger regions of the external field. Iron, cobalt, and nickel are examples of ferromagnetic materials. Magnetic moments play a significant role in the spin of ferromagnetic materials. These compounds are made up of a huge number of tiny units called domains. When a ferromagnetic substance is exposed to an external magnetic field, torque occurs in these domains. The domains rotate and remain parallel to the direction as a result of this.

Characteristics

• Ferromagnetic compounds are made up of a high number of tiny domains.
• When the external magnetic field is removed, these substances retain their magnetism.
• When heated over the curie point, certain materials become paramagnetic.
• Ferromagnetic compounds are highly attracted by the external magnetic field.
• When the magnetic field is non-uniform, these ferromagnetic materials tend to shift from the weaker to the stronger section of the field.
• When a ferromagnetic rod is placed in a homogeneous magnetic field, it will come to rest with its length parallel to the field’s direction.

Paramagnetic Substances 

When placed in an external magnetic field in the same direction as the externally applied field, paramagnetic substances become weakly magnetised. These materials are distinct from ferromagnetic and diamagnetic materials. They have a proclivity for moving from the weaker to the stronger magnetic field. Calcium, lithium, tungsten, aluminium, platinum, and other paramagnetic materials are examples. Each atom in a paramagnetic substance has a permanent magnetic dipole moment that is orientated due to the way the atoms spin. When there is thermal motion, however, the direction of magnetic moments might have arbitrary orientations. As a result, this substance’s net magnetic moment is zero.

Characteristics

• Every atom in this substance is thought to be a magnetic dipole with a magnetic moment as a result.
• These chemicals are attracted to the external magnetic field via a weak attraction.
• When placed in a non-uniform field, they travel from the weaker to the stronger area of the field.
• When the external magnetic field is removed, these compounds lose their magnetism.

Magnets of Various Types

There are three types of magnets:

• Permanent Magnets are magnets that retain their magnetic properties after they have been magnetised.
• Temporary Magnets are magnets that lose all of their magnetic properties when the magnetic field is removed.
• Electromagnets are materials that, when electricity is conducted through them, behave like magnets.

Earth’s Magnetic Field: What Causes It?

An electric current is generated by the movement of liquid iron at the Earth’s core, which causes magnetic fields. The magnetic field of the Earth is created deep within the planet’s core. Because charged metals moving through these fields produce electric currents, the cycle continues. The geodynamic is a self-sustaining loop of this type. The combined impact of magnetic fields creates a massive magnetic field that travels to the planet. The magnetic fields on Earth are caused by this.

Magnetism’s Properties

• Magnetic poles are always found in groups of two.
• Any magnets like poles repel one another, whereas unlike poles always attract each other.
• The stronger the magnetic force between two magnets, the smaller the space between them is.
• When a magnet is left dangling in the air, it will always fall into a north-south orientation.
• The North Pole of the magnet is the pole that points to the geographic north. The magnet’s South Pole is the pole that points in the direction of the geographic South.
• Magnets are always attracted to ferromagnetic materials.

Conclusion

When diamagnetic materials are exposed to an external magnetic field in the opposite direction as the applied field, they become weakly magnetised. Diamagnetism describes the sort of magnetism exhibited by certain materials. Ferromagnetic substances are those that get strongly magnetised in an external magnetic field in a direction that is the same as the direction of the externally applied field. Paramagnetic substances are those that become weakly magnetised when placed in an external magnetic field in the same direction as the externally applied field.