Abstract
Low-temperature heat capacity C(T) of the weakly electron-correlated SrNi2Ge2 122-layer compound undergoes a superconducting transition with onset at 1.4 K and a bulk T c =0.75 K, where heat-capacity jump ratio ΔC(T c )/γT c =0.88-1.05. A small average superconducting energy gap E g (ave)=2.21 kT c =0.14 meV is derived for this multi-gap superconductor. Similar results for isostructural SrPd2Ge2 include T c (onset)=3.5 K, bulk T c of 2.92 K, ΔC(T c )/γT c =0.70 and E g (ave)=2.54 kT c =0.64 meV. The higher T c onset could be associated with stoichiometric 1:2:2 grains in the polycrystalline samples. In addition, deviations of E g /kT c from the BCS ratio of 3.5 suggest that, just like their iron-based counterpart, these 122-layer germanides may also exhibit an unconventional, fully-opened multi-gap s-wave superconductivity.
Original language | English |
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Pages (from-to) | 148-155 |
Number of pages | 8 |
Journal | Journal of Low Temperature Physics |
Volume | 171 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 2013 Apr |
Keywords
- 122-layer germanide
- Heat capacity
- Superconducting materials
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- General Materials Science
- Condensed Matter Physics