On the destruction of the hidden order in URu

We present a study of the transport properties of the heavy-fermion URu2Si2 in pulsed magnetic field. The large Nernst response of the hidden order state is found to be suppressed when the magnetic field exceeds 35 T. The combination of resistivity, Hall and Nernst data outlines the reconstruction of the Fermi surface in the temperature-field phase diagram. The zero-field ground state is a compensated heavy-electron semi-metal, which is destroyed by magnetic field through a cascade of field-induced transitions. Above 40 T, URu2Si2 appears to be a polarized heavy-fermions metal with a large density of carriers whose effective mass rapidly decreases with increasing magnetic polarization