Hall Coefficient

The Hall Coefficient is the ratio of the induced electric field to the product of the current density and the applied magnetic field. It is a characteristic of the material from which the conductor is made , since its value depends on the type, number, and properties of the charge carriers that constitute the current. 

More Info

The Hall Effect is the production of a voltage difference across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current.

References

Wikipedia (https://en.wikipedia.org/wiki/Hall_effect)