Type: Article
Publication Date: 2018-12-26
Citations: 5
DOI: https://doi.org/10.1103/physrevb.98.214517
Superconductivity in the pseudobinary pnictides ${\mathrm{Ru}}_{0.55}{\mathrm{Rh}}_{0.45}\mathrm{P}$ and ${\mathrm{Ru}}_{0.75}{\mathrm{Rh}}_{0.25}\mathrm{As}$ is probed by muon spin relaxation and rotation ($\ensuremath{\mu}\mathrm{SR}$) measurements in conjunction with magnetic susceptibility, heat capacity, and electrical resistivity measurements. Powder x-ray diffraction confirmed the MnP-type orthorhombic structure (space group $Pnma$) and showed a nearly single phase nature with small impurity phase(s) of about 5% for both the samples. The occurrence of bulk superconductivity is confirmed with ${T}_{\mathrm{c}}=3.7$ K for ${\mathrm{Ru}}_{0.55}{\mathrm{Rh}}_{0.45}\mathrm{P}$ and ${T}_{\mathrm{c}}=1.6$ K for ${\mathrm{Ru}}_{0.75}{\mathrm{Rh}}_{0.25}\mathrm{As}$. The superconducting state electronic heat capacity data reveal weak-coupling single-band isotropic $s$-wave gap BCS superconductivity. Various normal and superconducting state parameters are determined which reveal a weak-coupling electron-phonon driven type-II dirty-limit superconductivity for both the compounds. The upper critical field shows a linear temperature dependence down to the lowest measured temperatures which is quite unusual for a single-band superconductor. The $\ensuremath{\mu}\mathrm{SR}$ data confirm the conventional type-II behavior and show evidence for a single-band $s$-wave singlet pairing superconductivity with a preserved time reversal symmetry for both the compounds.