An interference effect between the high-Tc superconductivity and martensitic transition in A15 compounds such as V3Si and Nb3Sn has been studied. It is found from the measurements of the sound velocity, sound attenuation, thermal dilation and the electrical resistance, that an occurrence of superconductivity interferes drastically with the developing tetragonal distortions caused by the martensitic transformation, but the high-Tc superconductivity in these compounds is only weakly affected by the presence of the martensitic transition. This unilateral interference effect is qualitatively consistent with the second-order band Jahn-Teller mechanism which means the Fermi level crossing the upper split band of the doubly degenerate Γ12 subbands. Discussions on Tc are given on the basis of the Fermi surface effect of Γ12 subbands.
ASJC Scopus subject areas
- Physics and Astronomy(all)