We report a ${}^{11}\mathrm{B}$ NMR measurement on the recently discovered superconductor ${\mathrm{Li}}_2{\mathrm{Pd}}_3\mathrm{B}$. The nuclear spin lattice relaxation rate $1∕T_1$ shows a well-defined coherence peak just below $T_c(H=1.46\mathrm{T})=5.7\mathrm{K}$, and the spin susceptibility measured by the Knight shift also decreases below $T_c$. These results indicate that the superconductivity is of conventional nature, with an isotropic gap. Our results also suggest that the $p$-electrons of boron and the $d$-electrons of palladium that hybridize with boron $p$-electrons are primarily responsible for the superconductivity.

• Received 16 March 2005

DOI:https://doi.org/10.1103/PhysRevB.71.220505