Field suppression of the heavy-fermion state in CeRu2Si2

摘要: Specific-heat measurements have been performed on a single-crystalline sample of the heavy-fermion compound ${\mathrm{CeRu}}_{2}$${\mathrm{Si}}_{2}$ in strong magnetic fields up to 20 T along tetragonal axis temperature interval 1.5T30 K. The linear electronic term specific heat (\ensuremath{\gamma}) passes through pronounced maximum at field ${\mathit{B}}^{\mathrm{*}}$\ensuremath{\simeq}7.8 T, where metamagneticlike transition occurs. For above ${\mathit{B}}^{\mathrm{*}}$, mass enhancement decreases gradually, resulting reduction effective by \ensuremath{\sim}80% with respect zero-field value. In high-field region, data analyzed using simple single-resonance-level model.