Influence of pressure on the transport, magnetic, and structural properties of superconducting Cr_0.0009NbSe₂ single crystal

Abstract

We investigate the superconducting critical current density (J c ), transition temperature (T c ), and flux pinning properties under hydrostatic pressure (P) for Cr 0.0009 NbSe 2 single crystal. The application of P enhances T c in both electrical resistivity ($0.38 K GPa À1 : 0 # P # 2.5 GPa) and magnetization ($0.98 K GPa À1 : 0 # P # 1 GPa) measurements, which leads to a monotonic increase in J c and flux pinning properties. The fielddependent J c at various temperatures under P is analyzed within the collecting pinning theory and it shows that dT c pinning is the crossover to dl pinning above the critical pressure (P c $0.3 GPa). Our systematic analysis of the flux pinning mechanism indicates that both the density of pinning centers and pinning forces greatly increase with the application of P, which leads to an enhancement in the vortex state. Structural studies using synchrotron X-ray diffraction under pressure illustrate a stable hexagonal phase without any significant impurity phase and lattice parameter reduction with P shows highly anisotropic nature. Results and discussionPowder X-ray diffraction (XRD) patterns were measured using the synchrotron energy source as shown in Fig. 1(a). The XRD pattern at room temperature was rened using the Rietveld renement method and it conrms the hexagonal crystalline phase with a space group of P6 3 /mmc. The lattice parameters This journal is Fig. 6 (a) J c (T) at 0.1 T under various P and it is fitted with the relation J c (T) f (1 À (T/T c )) a , (b) J c (T) at 0.09 GPa under various magnetic fields, (c) J c (T) at 0.98 GPa under selected magnetic fields and (d) J c (P) at 2 K; the solid lines represent linear fitting.This journal is

Peak in the superconducting transition temperature of the nonmagnetic topological line-nodal material CaSb$_2$ under pressure

“…For simplicity, we assume that only the c-axis lattice parameter shrinks and that the a-and b-axis lattice parameters do not change under pressure. Since CaSb 2 has a layered crystal structure, this assumption is more realistic even under hydrostatic pressure [23,24].…”

Peak in the superconducting transition temperature of the nonmagnetic topological line-nodal material CaSb2 under pressure

“…For simplicity, we assume that only the c-axis lattice parameter shrinks and that the a-and b-axis lattice parameters do not change under pressure. Since CaSb 2 has a layered crystal structure, this assumption is more realistic even under hydrostatic pressure [23,24]. The calculated pressure dependences of lattice parameters are listed in Table S1 [25].…”