Petrus Peregrinus was a 13th century physicist and mathematician who dwelved deep into the world of magnetism. Even though the concept of magnetism was an unknown one in those times, Professor Petrus chalked down his observations in black and white which he thought might serve as a basis of research in the upcoming years. 

Once, Petrus decided to venture upon a completely different experiment on magnets. This time he decided to break the bar magnet which was undoubtedly dipole(having both north and south pole). He was taken aback by the result. By seperating two magnets he expected to get a seperate north and south pole, but instead he got two new smaller bar magnets with their north and south pole.

So basically, a north pole (or a south pole)cannot exist independently. Long story short - magnets are always dipole. It's seemingly impossible to seperate the poles. But the question is - "Why does a magnet need to be dipole in the first place?"

As we have discussed in the previous blog, electricity and magnetism are the two sides of the same coin. So if an electric monopole can exist why not the same for a magnet? 


You may suggest that according to the famous Maxwell's equations, the divergence of a magnetic field(B) is always zero, while for an electric field(E) it's clearly non-zero(it depends on the charge density 'ρ')...wait a second, what is divergence? Let's keep it booked for another blog. For now just keep in mind that for a magnetic field if we choose any part of the same then--the amount of field lines heading towards one pole will be the same as the amount of field lines heading towards the other. Basically the first equation is a mathy description of the experiment carried out by Petrus(a north pole must be accompanied by a south pole in order to constitute a magnetic field). 

But this argument is insufficient to nullify the possibility of the existence of magnetic monopoles. Maxwell clearly didn't believe that monopoles can exist...but what if they really do?

                             Electric Monopole

The Odyssey:

Paul Dirac in the 1930's was of the view that the existence of magnetic monopoles will unravel the underlying reason for the quantization of electric charge  (Charges occur only in the integer multiples of the elementary charge, that is ±1.6 x 10^-12 C). Hence scientists decided to venture into a new journey of finding the Magnetic monopole. 

 A headstart in research:

Felix Flicker, a condensed matter physicist from England, in a recent lecture on Magnetic Monopoles, talked about his experience on being part of the team which (for the first time in history) came somewhat close in finding a magnetic monopole.

Candidate materials for finding magnetic monopoles: 
  • Dysprosium Titranate
  • Holmium Titanate
              Structure of Dysprosium Titanate

This compound(also known as spin ice) is made up of tetrahedral bonds which when exposed to extremely low temperatures (0.6 - 2 Kelvin) observe their atoms with their own magnetic properties. Of the four atoms that form the vertices of a pyramid, two have magnetic moments (spin) that point inward and two point outward(hence divergence is zero). 



When any one of the atoms is flipped, an imbalance is created which creates a concentrated region of a pole(north or south), similarly if other atoms are continuously flipped, it forms a track, followed by the seperated pole which is drawn away from its partner. Therefore a magnetic monopole is created. 

Recently scientists have used muons which decay inside the spin ice to release positrons which in turn show that magnetic monopoles not only are created inside the spin ice but also is moving. Just like a moving electric current constitutes electricity, similarly a moving magnetic current is known as 'Magnetricity'. Quite a fancy name I suppose. 

Basic Limitation:
This experiment shows that magnetic monopoles exist but not convincingly, since the magnetic current cannot flow out of the material. Even Though the scientific community has not been fully convinced on the existence of monopoles, it is certainly a major progress.

Uses of Magnetic Monopoles:
When asked about its uses, scientists are skeptical that it has even one implementation.

But let us remind ourselves the famous incident of Faraday, when he was asked about the uses of electricity. He simply said,"What is the use of a new born child?"