Effect of magnetic field on the electrical properties:

Since the electrical properties of the materials are determined by the nature of flow of electrons and considering the charge nature of electrons, the flow is expected to be affected/modified by the presence of local or applied magnetic field.

As a result, the resistance of the materials changes depending on the change in the electron motion. This effect is typically called as magnetoresistance (MR).

If we consider a simple semi-classical argument, the force on an electron is due to the Lorentz force and the electric field,

If the current density can be written as , where V is the volume of the sample and N the number of electrons, then with the relaxation time approximation we can write

and therefore