Low temperature specific heat of the heavy fermion superconductor PrOs4_4Sb12_{12}

We report the magnetic field dependence of the low temperature specific heat of single crystals of the first Pr-based heavy fermion superconductor PrOs$_4$Sb$_{12}$. The low temperature specific heat and the magnetic phase diagram inferred from specific heat, resistivity and magnetisation provide compelling evidence of a doublet ground state and hence superconductivity mediated by quadrupolar fluctuations. This establishes PrOs$_4$Sb$_{12}$ as a very strong contender of superconductive pairing that is neither electron-phonon nor magnetically mediated.Comment: 4 pages, 4 figure

Specific-heat study of the triangular-lattice antiferromagnet RbCuCl

We report on the magnetic phase diagram of the distorted triangular-lattice antiferromagnet RbCuCl3 for a magnetic field applied parallel to the basal plane (B⊥c). High-resolution measurements of the specific heat and of the magnetocaloric effect have been performed in magnetic fields up to 14 T. The high-field specific-heat data reveal the existence of an intermediate phase between the paramagnetic and the frustrated antiferromagnetic phase