Corbino disk

(electromagnetism) A variable-resistance device utilizing the effect of a magnetic field on the flow of carriers from the center to the circumference of a disk made of semiconducting or conducting material.

A conducting disk with concentric inner and outer electrical contacts, which can be placed in a magnetic field parallel to its axis. In zero applied field the lines of current are simply radial, but in the presence of an axial magnetic field they lengthen by spiraling. This spiraling occurs because the geometry of the disk is such that the Lorentz force acting on the charge carriers is not counterbalanced by a Hall-effect electric field. The resistance of the disk increases as the field increases, largely as a result of the geometrical magnetoresistance effect associated with the lengthening of the current path. Corbino disks have been used only rarely in practical devices since they have a low overall resistance and correspondingly large power dissipation. See also Hall effect; Magnetoresistance.