Breakdown, Magnetic

the tunneling transition of electrons in a metal from one of the classical orbits in a magnetic field to another. It is observed at liquid helium temperatures in single crystals of a number of metals when they are placed in a magnetic field. Under these conditions, the probability of quantum tunneling transitions far exceeds the probability of scattering, that is, transitions caused by collisions. Magnetic breakdown leads to a rearrangement of the electron energy spectrum in a metal and to other macroscopic effects that are brought about by this rearrangement. It is manifested in galvanomagnetic phenomena and in the De Haas-Van Alphen effect, and it affects other properties of metals that depend on the magnetic field. One of the most significant phenomena exhibited in magnetic breakdown is the abnormally high amplitude of the oscillations in a number of the metal’s characteristics, such as the magnetoresistance and the Hall field that are observed when the magnetic field intensity is varied.