Year: 2006
Type: article
Abstract: The magnetic field dependence of low temperature specific heat in ${\mathrm{YNi}}_{2}{\mathrm{B}}_{2}\mathrm{C}$ was measured and analyzed using various pairing order parameters. At a zero magnetic field, the two-gap model, which has been successfully applied to ${\mathrm{MgB}}_{2}$ and the point-node model, appear to describe the superconducting gap function of ${\mathrm{YNi}}_{2}{\mathrm{B}}_{2}\mathrm{C}$ better than other models based on the isotropic $s$-wave, the $d$-wave line nodes, or the $s+g$ wave. The two energy gaps, ${\ensuremath{\Delta}}_{L}=2.67\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ and ${\ensuremath{\Delta}}_{S}=1.19\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$, are obtained. The observed nonlinear field dependence of the electronic specific heat coefficient, $\ensuremath{\gamma}(H)\ensuremath{\sim}{H}^{0.47}$, is quantitatively close to the $\ensuremath{\gamma}(H)\ensuremath{\sim}{H}^{0.5}$ expected for nodal superconductivity or that can be qualitatively explained using a two-gap scenario. Furthermore, the positive curvature in ${H}_{c2}(T)$ near ${T}_{c}$ is qualitatively similar to that in the other two-gap superconductor ${\mathrm{MgB}}_{2}$.
Source: Physical Review B
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2042897669