Magnetization in the ultraquantum limit.

The magnetization below and far above the quantum limit for small Fermi surface orbits has been measured in the metallic compound LaRhIn(5). The magnetization due to a pocket of Fermi surface that comprises less than 1 part in 10(4) of the total Brillouin zone volume, and for which the quantum limit is approximately 7 T, leads to the appearance of an overall sample magnetic moment at fields between 7 and 32 T. This moment arises from diamagnetic currents produced by electrons in the ultraquantum limit. A model calculation of the origin and magnitude of the effect is in excellent agreement with the measured field dependence of the induced magnetization.