Unconventional superconductivity and magnetism in $\mathrm{CeP}{\mathrm{t}}_3\mathrm{S}{\mathrm{i}}_{1-\mathrm{x}}\mathrm{G}{\mathrm{e}}_{\mathrm{x}}$

Abstract

$\mathrm{CeP}{\mathrm{t}}_3\mathrm{Si}$ is a novel ternary compound exhibiting antiferromagnetic order at $T_N\approx 2.2$ K and superconductivity (SC) at $T_c\approx 0.75$ K. Large values of $H_{c2}^{\prime }\approx -8.5$ T/K and $H_{c2}(0)\approx 5$ T indicate Cooper pairs formed out of heavy quasiparticles. The mass enhancement originates from Kondo interaction with a characteristic temperature $T_K\approx 8$ K. NMR and $\mu$SR measurements evidence coexistence of SC and long range magnetic order on a microscopic scale. Moreover, $\mathrm{CeP}{\mathrm{t}}_3\mathrm{Si}$ is the first heavy fermion SC without an inversion symmetry. This gives rise to a novel type of the NMR relaxation rate $1/T_1$ which is very unique and never reported before for other heavy fermion superconductors. Studies of Si/Ge substitution allow us to establish a phase diagram.

6 pages, 9 figures, SCES'04