Portal de Periódicos da CAPES

High-pressure effect on the superconductivity of YB 6

2014; American Physical Society; Volume: 90; Issue: 4 Linguagem: Inglês

10.1103/physrevb.90.045136

1550-235X

S. Gabáni, I. Takáčová, G. Pristáš, E. Gažo, К. Flachbart, Takao Mori, D. Braithwaite, Martin Míšek, Konstantin V. Kamenev, M. Hanfland, P. Samuely,

Superconductivity in MgB2 and Alloys

Pressure effect on superconducting properties of two YB6 samples (Tc = 5.9 and 7.5 K) were investigated by measurements of electrical resistivity, magnetic susceptibility, and X-ray diffraction in the pressure range up to 320 kbar. Magnetoresistivity measurements down to 60 mK and up to 47 kbar have shown a negative pressure effect on Tc as well as on the third critical field Hc3 with the slopes dlnTc/dp = -0.59%/kbar and dlnHc3/dp = -1.1%/kbar, respectively. The magnetic susceptibility measurements evidenced that the slope of dlnTc/dp gradually decreases with pressure reaching 3 times smaller value at 112 kbar. The lattice parameter measurements revealed the volume reduction of 14% at 320 kbar. The pressure-volume dependence is described by the Rose-Vinet equation of state. The obtained relative volume dependence dlnTc/dlnV analyzed by the McMillan formula for Tc indicates that the reduction of the superconducting transition temperature is mainly due to hardening of the Einstein-like phonon mode responsible for the superconducting coupling. This is confirmed by the analysis of the resistivity measurements in the normal state up to T = 300 K performed at pressures up to 28 kbar.