UC Irvine

Extremal cross-sectional areas and effective masses of the Fermi surface of LaB6 in the (100) and (110) planes have been measured using the de Haas-van Alphen (dHvA) effect. In addition, measurements of the field dependence of the magnetoresistance in the (100) plane have also been performed which show the existence of open orbits in certain directions and suggest the presence of magnetic breakdown. Much of the dHvA data are consistent with a set of nearly spherical ellipsoids located at the points X of the Brillouin zone and connected by necks which intersect the M line; magnetic breakdown across the necks must be postulated to explain the remaining data. The proposed Fermi surface is consistent with the discrete variational band-structure calculations of Walch et al. © 1976 The American Physical Society.