Evolution of Fermi Surface Properties in CexLa1-xB6 and PrxLa1-xB6

We report the de Haas–van Alphen (dHvA) effect measurements of the Fermi surface properties in LaB 6 , Ce x La 1- x B 6 ( x = 0.1, 0.25, 0.5, 0.75, 1.0) and Pr x La 1- x B 6 ( x = 0.25, 0.5, 0.75, 1.0) with particular attention to the spin dependence of the Fermi surface properties. The Fermi surface shape and dimension of Ce x La 1- x B 6 change considerably with Ce concentration, while those of Pr x La 1- x B 6 change very slightly up to x = 0.75, and in PrB 6 the Fermi surface splits into the up and down spin Fermi surfaces. The effective mass of Ce x La 1- x B 6 increases considerably with Ce concentration and is nearly proportional to the number of Ce ions, whereas that of Pr x La 1- x B 6 increases slightly with Pr concentration. In Ce x La 1- x B 6 the effective mass depends very strongly on field and increases divergently with decreasing field, while that of Pr x La 1- x B 6 increases slightly with decreasing field. The contribution to the dHvA signal from the conduction electrons of one spin dire...