A proton has spin and magnetic moment just like an electron. Why then its effect is neglected in magnetism of materials?

Probability of a proton is given by

e is the electric charge

is the mass of the proton

h is the Plank’s constant

Probability of an electron is given by

is the mass of the electron

We know that the mass of the proton is greater than the mass of the electron.

So

That implies

From the above we can conclude that probability of the electron is very higher than the probability of the proton. That’s why the effect of proton in magnetism materials is neglected.