Ames Laboratory; Physics and Astronomy
Physics and Astronomy, Ames Laboratory
Physical Review B
The pressure dependence of the magnetic and superconducting transitions and that of the superconducting upper critical field are reported for CaK(Fe1-xNix)(4)As-4, the first example of an Fe-based superconductor with spin-vortex-crystal-type magnetic ordering. Resistance measurements were performed on single crystals with two substitution levels (x = 0.033,0.050) under hydrostatic pressures up to 5.12 GPa and in magnetic fields up to 9 T. Our results show that, for both compositions, magnetic transition temperatures T-N are suppressed upon applying pressure; the superconducting transition temperatures T-c are suppressed by pressure as well, except for x = 0.050 in the pressure region where T-N and T-c cross. Furthermore, the pressure associated with the crossing of the T-N and T-c lines also coincides with a minimum in the normalized slope of the superconducting upper critical field, consistent with a likely Fermi-surface reconstruction associated with the loss of magnetic ordering. Finally, at p similar to 4 GPa, both Ni-substituted CaK(Fe1-xNix)(4)As-4 samples likely go through a half-collapsed-tetragonal phase transition, similar to the parent compound CaKFe4As4.
Department of Energy Subject Categories
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Iowa State University Digital Repository, Ames IA (United States)