Low temperature specific heat of the heavy fermion superconductor PrOs_4Sb_{12}
R. Vollmer, A. Faißt, C. Pfleiderer, H. v. Löhneysen, E. D. Bauer, P.-C. Ho, M. B. Maple
Abstract
We report the magnetic field dependence of the low temperature specific heat of single crystals of the first Pr-based heavy fermion superconductor PrOs_4Sb_{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_4Sb_{12} as a very strong contender of superconductive pairing that is neither electron-phonon nor magnetically mediated.