Anisotropic collapse of electronic correlations in the ferromagnet UGe$_2$ under high magnetic field

We present electrical-resistivity measurements on the prototypical heavy-fermion ferromagnet UGe$_2$ under pulsed magnetic field up to 60 T. An anisotropic field-induced suppression of the electronic correlations is revealed. The electrical resistivity strongly decreases when a magnetic field 𝐇 is applied along the easy magnetic axis 𝐚, while it remains almost unchanged when 𝐇 is applied along the hard magnetic axes 𝐛 and 𝐜. The field-induced destabilization of the ferromagnetic state is also anisotropic: the anomaly at the Curie temperature 𝑇𝐶 disappears in fields higher than ≳1T for 𝐇∥𝐚 and in fields higher than ≳20T for 𝐇∥𝐛,𝐜. At temperatures below 2 K, we observe quantum oscillations in fields larger than 50 T applied along 𝐛, which support the presence of a two-dimensional Fermi surface similar to that previously observed at low fields.