Specific heat, magnetic susceptibility, resistivity and thermal expansion of the superconductor ZrB12

  title={Specific heat, magnetic susceptibility, resistivity and thermal expansion of the superconductor ZrB12},
  author={Rolf Lortz and Y. Wang and Satoko Abe and C Meingast and Yu. B. Paderno and Vladimir B. Filippov and Alain F. Junod},
  journal={Physical Review B},
In an attempt to clarify conflicting published data, we report new measurements of specific heat, resistivity, magnetic susceptibility, and thermal expansivity up to room temperature for the 6 K superconductor ZrB12, using well-characterized single crystals with a residual resistivity ratio 9. The specific heat gives the bulk result 20/ kBTc=3.7 for the superconducting gap ratio, and excludes multiple gaps and d-wave symmetry for the Cooper pairs. The Sommerfeld constant n=0.34 mJ K 2 gat 1… 

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