Pressure induced softening of YB₆: pressure effect on the Ginzburg-Landau parameter κ=λ/ξ

الأصل · EN

Measurements of the transition temperature Tc, the second critical filed Hc₂ and the magnetic penetration depth λunder hydrostatic pressure (up to 9.2 kbar) in the YB₆ superconductor were carried out. A pronounced and negative pressure effects (PE) on Tc and Hc₂ with dTc/dp=-0.0547(4) K/kbar and μ₀dHc₂(0)/dp =-4.84(20) mT/kbar, and zero PE on λ(0) were observed. The PE on the coherence length dξ(0)/dp=0.28(2) nm/kbar was calculated from the measured pressure dependence of Hc₂(0). Together with the zero PE on the magnetic penetration depth λ(0), our results imply that the Ginzburg-Landau parameter κ(0)=ξ(0)/λ(0) depends on pressure and that pressure "softens" YB₆, e.g. moves it to the type-I direction.