Almost localized fermions in a magnetic field: Properties at the metamagnetic transition

We present applied magnetic-field dependences of the magnetization, linear specific heat, and de Haas-van Alphen oscillations for the almost-localized Fermi liquid (ALFL) close to the metamagnetic transition. The analysis is performed within the mean-field slave-boson approach, which provides a realistic description in the strong applied-field limit. The Fermi liquid is thermodynamically unstable at the metamagnetic point, at which it is proposed that the system transforms into a statistical spin liquid (SSL) in the partially-filled-band case. This transition corresponds to the Mott-Hubbard localization in the half-filled band situation. The effective mass in the ALFL phase is spin dependent and large, whereas it is spin independent and has a band value in the SSL phase.