Pressure induced softening of YB_6: pressure effect on the Ginzburg-Landau parameter \kappa=\lambda/\xi

TL;DR

This study investigates how hydrostatic pressure affects the superconducting properties of YB_6, revealing that pressure softens the material and influences the Ginzburg-Landau parameter, with notable effects on T_c and H_{c2}.

Contribution

It provides the first detailed measurement of pressure effects on T_c, H_{c2}, and mbda in YB_6, showing pressure-induced softening and changes in the Ginzburg-Landau parameter.

Findings

Pressure decreases T_c and H_{c2} in YB_6.

Pressure has no effect on the magnetic penetration depth mbda.

The Ginzburg-Landau parameter ppa depends on pressure, indicating softening.

Abstract

Measurements of the transition temperature T_c, the second critical filed H_{c2} and the magnetic penetration depth \lambda under hydrostatic pressure (up to 9.2 kbar) in the YB_6 superconductor were carried out. A pronounced and {\it negative} pressure effects (PE) on T_c and H_{c2} with dT_c/dp=-0.0547(4) K/kbar and \mu_0dH_{c2}(0)/dp =-4.84(20) mT/kbar, and zero PE on \lambda(0) were observed. The PE on the coherence length d\xi(0)/dp=0.28(2) nm/kbar was calculated from the measured pressure dependence of H_{c2}(0). Together with the zero PE on the magnetic penetration depth \lambda(0), our results imply that the Ginzburg-Landau parameter \kappa(0)=\xi(0)/\lambda(0) depends on pressure and that pressure "softens" YB_6, e.g. moves it to the type-I direction.