Fermi surface changes across the Neel phase boundary of NdB6

We report de Haas-van Alphen measurements in both the antiferromagetic and paramagnetic regimes of NdB6, which are shown to be separated by a second order upper critical field for antiferromagnetic ordering of H-c approximate to 30 T when the magnetic field is parallel to [001]. The Fermi surface changes across the transition provide an ideal example of a system in which the effect of a one-dimensional magnetic periodic potential on doubling the unit cell (as originally predicted by Slater [Phys. Rev. 82, 538 (1951)]) can be tuned by varying only the magnetic field. The Fermi surface within the paramagnetic phase resembles that observed in other hexaborides such as LaB6 but with additional exchange splitting effects and weak correlations.