High-field and quantum oscillatory effects in the magnetoresistance of AuSn

High-field magnetoresistance measurements have been used to investigate the Fermi surface of the metallic compound AuSn. The maximum field used was 150 kG and the maximum resistance ratio of the single crystal samples was 157. The results indicate that AuSn is a compensated metal and that its Fermi surface supports open orbits along [0001], 〈 101̄0 〉 and〈 112̄0 〉 directions. Magnetoresistance oscillations periodic in inverse field were observed when the field was in the basal plane and when the current direction was not in the basal plane. Three sets of frequencies were measured in the basal plane and these agreed well with the de Haas-van Alphen results of other workers. The amplitude of the oscillations was approx. 0.1-1 per cent of the steady magnetoresistance. In the absence of a band structure calculation, the topological results are compared with a nearly-free-electron Fermi surface model in the single zone scheme. The experimental results are found to be consistent with the model and with the de Haas-van Alphen results insofar as open orbit directions are concerned. The possible influence of magnetic breakdown on the state of compensation and on the origin of the resistivity oscillations is discussed.