Origin of Magnetism
The origin of magnetism is explained by taking into consideration the circular motion of electrons. The electrons present inside the atoms move in circular orbits around the nucleus; this is similar to a circular coil carrying current. The electron's orbital motion gives rise to the orbital magnetic moment.
The electrons tend to spin around in their own axis, thus creating a spin magnetic moment. The magnetic moment of an atom is the result of the vector sum of the orbital and spin magnetic moment. Based upon the magnetic properties, the magnetic substances are classified into three groups, namely diamagnetic, ferromagnetic, and paramagnetic.
Short Brief on Diamagnetic Substances
Diamagnetic Definition
Diamagnetic substances are magnetized weakly when placed in an external magnetic field in a direction that is opposite to the applied field. The type of magnetism that is exhibited by these substances is known as diamagnetism. Examples of diamagnetic substances are copper, gold, antimony, bismuth, silver, lead, silicon, mercury, etc.
The electron's orbital motion gives rise to an orbital magnetic moment. In addition to this, the electrons tend to spin around their own axis, creating a spin magnetic moment. Electrons in an atom can have a clockwise or anticlockwise spin. In a similar way, the electrons can revolve around the nucleus in a clockwise or anticlockwise direction.
In the case of diamagnetic substances, the magnetic moments of atoms and the orbital magnetic moments have been oriented in such a manner that the vector sum of an atom’s magnetic moment becomes zero.
Characteristics
In a diamagnetic substance, the magnetic moment of every atom is calculated to be zero.
An external magnetic field can repel them weakly.
If diamagnetic substances are placed in a non-uniform magnetic field, then the substances move towards the weaker side of the field from the stronger side.
When these substances are placed in an external magnetic field, they get weakly magnetized in the direction that is opposite to the direction of the field.
Magnetic susceptibility turns out to be negative in diamagnetic substances.
Ferromagnetic Substance
Substances that get magnetized strongly in an external magnetic field in a direction which is the same as the direction of the externally applied field are known as ferromagnetic substances. These types of substances retain their magnetic moment even after the removal of the magnetic field. Ferromagnetic substances tend to move from weaker to stronger parts of the external field. Some examples of ferromagnetic substances are iron, cobalt, and nickel.
In the ferromagnetic substances spin, magnetic moments have a large contribution. These substances consist of a large number of small units that are known as domains. These domains experience torque when a ferromagnetic substance is exposed to an external magnetic field. Due to this, the domains rotate and remain parallel to the direction of the field.
Characteristics
A large number of small domains make ferromagnetic substances.
These substances do not lose their magnetism when the external magnetic field is removed.
These substances become paramagnetic when they are heated above the curie point.
The external magnetic field strongly attracts ferromagnetic substances.
These ferromagnetic materials tend to move from the weaker to the stronger part of the field when the magnetic field is non-uniform.
If a rod of ferromagnetic substance is placed in a uniform magnetic field, the rod comes to rest with its length being parallel to the direction of the field.
Paramagnetic Substances
Substances that get magnetized weakly when placed in an external magnetic field in the same direction as the direction of the externally applied field are known as paramagnetic substances. These substances are different from ferromagnetic and diamagnetic substances. They have a tendency to move from the weaker to the stronger part of the magnetic field. Some examples of paramagnetic substances are calcium, lithium, tungsten, aluminum, platinum, etc.
In a paramagnetic substance, each atom has a permanent magnetic dipole moment because of the way they spin, the magnetic moments are oriented. However, the direction of magnetic moments can have random orientations when there is thermal motion. Due to which the net magnetic moment of this substance is zero.
Characteristics
Every atom in this substance is considered as a magnetic dipole that has a resultant magnetic moment.
The external magnetic field creates a weak attraction to these substances.
They move from weaker to the stronger part of the field when placed in a non-uniform field.
These substances lose their magnetism when the external magnetic field is removed.
Types of Magnets
The 3 types of magnets are-
Permanent Magnet- Permanent Magnets are magnets that never lose their magnetic property once they're magnetized.
Temporary Magnet- Temporary Magnets are magnets that lose their complete magnetic property when the magnetic field is removed.
Electromagnets- Electromagnets are material that behaves like a magnet when electricity is passed through them.
Cause of Magnetic Field on Earth
The flow of liquid iron at the center of the Earth generates an electric current that produces magnetic fields. Earth’s magnetic field is produced very deep down in the core of the planet.
The cycle continues because the Charged metals passing through these fields produce their electric currents. This type of self-sustaining loop is called the geodynamo. The collective effect of magnetic fields produces 1 vast magnetic field going to the planet. This is the reason behind the magnetic fields on Earth.
Properties of a Magnet
Magnetic poles always occur in pairs.
The like poles of any magnet will repel each other while the unlike poles will always attract each other.
The smaller the distance between 2 magnets, the greater magnetic force there exists between the 2 magnets.
Whenever a magnet is left suspended freely in the air, it always eventually rests in a north-south direction.
The pole that points towards the geographic north is called the North Pole of the magnet. The pole that points towards the geographic South is called the South Pole of the magnet.
Magnets always attract ferromagnetic substances.
It is noticeable that, when any magnet is submerged in some iron filings, the iron filings stick only to the end of that magnet. This happens because the magnetic attraction is maximum at the ends of any magnet. These ends are also called the magnet poles.
Conclusion
This article presents you with a clear picture of Diamagnetism, Ferromagnetism and Paramagnetism. You can check out Vedantu for more information.
FAQs on Diamagnetism,Ferromagnetism,and Paramagnetism
1. Differentiate Between Paramagnetic and Diamagnetic Substances.
Paramagnetic Substances | Diamagnetic Substances |
The term paramagnetic refers to the attraction of material to an external magnetic field. | The term diamagnetic refers to the repulsion of material from an external magnetic field. |
These substances have at least one unpaired electron. | These substances have no unpaired electrons. |
Magnetic field direction is the same as that of the external magnetic field. | Magnetic field direction is opposite to the direction of the external magnetic field. |
They exhibit stronger magnetic behavior. | They exhibit weaker magnetic behavior and easily get surpassed in the presence of stronger magnetic properties. |
2. Differentiate Between Diamagnetic and Ferromagnetic Substances.
Ferromagnetic Substances | Diamagnetic Substances |
These substances are always in a solid-state. | These substances can be in a solid, liquid, or gaseous state. |
These substances are strongly attracted by magnets. | These substances are feebly repelled by magnets. |
They move from the weaker to the stronger part of the field when placed in a non-uniform magnetic field. | They move from stronger to weaker parts of the field when placed in a non-uniform magnetic field. |
They can turn into paramagnetic substances if heated above the curie point. | Temperature has no impact on these substances. |
3. What is a Magnetic Field?
A magnetic field is a vector field in the vicinity of a hanging electric field, magnet, or electric current in which the effects of magnetic forces are noticeable. The area surrounding a magnet in which the effect of magnetism is sensed is called a magnetic field. A magnetic field is used as a tool to define the distribution of the magnetic force, in the space around and within something magnetic in nature. It is produced by repositioning electric charges and intrinsic magnetic moments of the elemental particles associated with a fundamental quantum effect called spin. The Symbol for magnetic field is(B,H) and is represented by unit Tesla(T). Students can download the PDF format from Vedantu website to learn.
4. How is the magnetic field created by current conducting conductors?
The magnetic field occurs when a charge is in motion. It was found that a magnetic field is created every time an electrical charge gets into motion. According to Ampere's law, the magnetic field at a distance r from a prolonged current-carrying conductor I can be found out by the following equation-
B=μ0I/2πrB
(where μ0 is a special constant called the permeability of free space and μ0=4π×10−7T⋅m/Aμ0=4π×10−7T⋅m/A).
This is how the magnetic field is created by current conducting conductors.
5. What is the Right-Hand Thumb Rule?
Substances with greater permeability maintain the ability to concentrate on magnetic fields. As the magnetic field has direction, it is a vector quantity and for finding the direction of a conventional current flowing through a straight wire, the Right-Hand rule is used. To use the Right-Hand Thumb Rule, the student has to imagine gripping their right hand around the wire. If their thumb is pointing in the current direction, their fingers will show the direction of the respective magnetic field, which wraps on the wire.
6. What is Magnetic Field Intensity?
Magnetic Field Intensity is defined as the force encountered by the unit north pole at that point. It is the strength of a magnetic field at a given point. Magnetic field Intensity is represented as a vector (H) and is defined as the ratio of the MMF needed to create a certain Flux Density (B) within a particular material per unit length of that material.
The formula for Magnetic Field Intensity-
H = (B/μ) − M
(where 'B' is magnetic flux density, 'M' is magnetization and 'μ' is magnetic permeability). The unit of magnetic field intensity is also Tesla. 1 tesla (1 T) is the field intensity causing 1 newton (1 N) of force per ampere of current per meter of a given conductor.
7. Why are magnetic flux lines important?
Magnetic flux lines are important because-
Magnetic flux lines help to indicate the direction of the magnetic field.
These are the lines in a magnetic field whose tangent at any point, gives the field direction and density gives the magnitude of the field.
The magnetic field intensity relies on the number of magnetic field lines. Magnetic Field lines are more at the poles and thus the magnetic field at the poles is stronger.
The strength of a magnetic field depends on the number of magnetic field lines in a given area.
