de Haas-van Alphen effect and the electronic state in CePtAl

Abstract We have done the de Haas-van Alphen (dHvA) experiment for a canted ferromagnet CePtAl. The detected dHvA branches are so many in number, revealing the multiply connected small Fermi surfaces. The cyclotron effective masses are relatively large, ranging from 0.4 m 0 to 10 m 0 . These Fermi surfaces are approximately explained on the basis of the results of energy band calculations of LaPtAl.