Measure of Dipoles

Ever wonder what makes magnets attract each other? It’s because of their dipoles, which are the region of space in which a magnetic field is generated. Dipole moments are an indication of how strong a magnet is. The dipole moment can also measure the polarisability or how easy it is for a magnet to pick up an external magnetic field and align its dipole with it. Magnetic dipoles have a strength proportional to the number of poles an object has.

Dipoles are often confused with magnets and are often used interchangeably in textbooks and other instructional materials. 

About Dipoles

Dipole: An object that contains a pair of equal and opposite poles called “dipoles.”

Pole: A magnetic pole is a north or south pole. A north pole will be attracted to the south pole of another magnet, while a south pole will be attracted to the north pole of another magnet. If two magnets are placed on top of each other, their magnetic fields combine and they become stronger. This is called a “dipole magnet.”

Dipoles are used to determine the polarity of magnets. Dipole moments are measured in Debye, D (from the earlier CGS measurement system). A Debye equals 3.34 × 10 J·m, i.e., one-third of an atomic magneton (a unit of the magnetic moment). The magnetic dipole moment describes the direction and intensity of net magnetization when all external influences are excluded.

A dipole can be created by a small rod of ferromagnetic material placed in a magnetic field or by placing magnetic material inside an electrically conducting circular piece of metal (such as a solenoid). The dipole moment is generated within the material itself and depends solely on its properties.

To find out what sort of object we are dealing with, it is important to define what “dipole” means.

A “dipole” is a magnetic field made up of two opposite poles pointing in the same direction. In a simple case, an electric dipole consists of an electric charge (and therefore current) separated into two equal but opposite parts. In this case, we are dealing with a magnetic dipole and a magnet is simply one such object. For example, the Earth possesses both a magnetic field and an electric current that is part of the Earth’s dipole system, which results in its being a magnet.

The most common magnetic dipole consists of two identical bar magnets placed end to end with their poles aligned. In this case, the magnetic field vectors form an angle of 90 degrees between their ends and each other because “opposite poles attract.” The magnetic field of an ideal magnet has the same shape as a dipole and it does not matter if the end of the magnet is in or out of the page.

About Dipole Moments

Dipole moment is the measure of magnetic dipoles.

The magnetic moment is a vector that characterises the magnet’s overall magnetic properties. To give the total magnetic moment, a dipole that can be added to it, as if it were an isolated dipole, is called a diamagnetic dipole.

Then, the total magnetic moment of an object is the sum of all of its magnetic dipoles: M = ∑ i = 1 n M i, where “n” is the number of significant poles or dipoles. If a material were made entirely of identical dipoles, then it would have a net magnetic moment equal to the product of all its dipole moments.

Total magnetic moment: Is the sum of all the individual magnetic dipole moments of a material.

Electric Dipole

An electric dipole is an electric charge (and current) separated into two equal but opposite parts perpendicular to each other.

Electric dipolar polarisation is the one in which the charges or currents are evenly distributed, unlike those associated with chemical bonds or molecular structure. Mainly the electrons within atoms and molecules are not only bound by chemical forces but also held together by electromagnetic forces. This polarisation, although dipolar, is not the same as an electric dipole.

Differences between a Dipole and a Dipole Moment

• Diamagnetism and paramagnetism both have dipole moments.
• Magnets can be isomorphic (have the same poles) or antisymmetric, which allows them to be equivalent.
• A dipole does not have to be a magnet; D-state matter, for instance, is a nonmagnetic dipole.
• Dipole moment may or may not be a scalar.
• The “strength” of a magnetic dipole is measured by its dipole moment, which comes from the strength of the magnetic field and its directionality.
• Magnets are not a logical family of objects but rather the result of their magnetic dipole moments. Any object with different magnetic dipole moments but the same type of arrangement of poles will be magnetically equivalent, resulting in different magnetic strengths.

Conclusion

In conclusion, we can say that Dipole and dipole moments were discovered in the early 1800s. Then there came a big development in which Faraday found many magnetic dipoles, then Maxwell took that further and created 3 Laws of Electricity and Magnetism.

In 1861, Faraday published his explanation of how diamagnetic and paramagnetic bodies behave when subjected to a magnetic field and show dipole moment.

The concept of a dipole magnet has been generalised with the development of the theories of electrostatics and electrodynamics. In Maxwell’s theory of electromagnetism, the magnetic field is a special case of a potential field.