Abstract
The interplay between unconventional superconductivity and quantum critical ferromagnetism in the U-Ge compounds represents an open problem in strongly correlated electron systems. Sample quality can have a strong influence on both of these ordered states in the compound UCoGe, as is true for most unconventional superconductors. We report results of a different approach at UCoGe crystal growth using a floating-zone method with potential for improvements of sample quality and size as compared with traditional means such as Czochralski growth. Single crystals of the ferromagnetic superconductor UCoGe were produced using an ultra-high vacuum electron-beam floating-zone refining technique. Annealed single crystals show well-defined signatures of bulk ferromagnetism and superconductivity at Tc∼2.6K and Ts∼0.61K, respectively, in the resistivity and heat capacity. Scanning electron microscopy of samples with different surface treatments shows evidence of an off-stoichiometric uranium-rich phase of UCoGe collected in cracks and voids that might be limiting sample quality.
| Original language | English (US) |
|---|---|
| Article number | 054803 |
| Journal | Physical Review Materials |
| Volume | 5 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2021 |
Funding
Work at Los Alamos National Laboratory was performed under the auspices of the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering. This work made use of the Jerome B. Cohen x-Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (Grant No. DMR-1720139) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF Grant No. ECCS-1542205). Support for crystal growth was provided by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences (BES), Division of Material Sciences and Engineering under Award No. DE-FG02-05ER46248 (W.P.H.). This work made use of the EPIC facility of Northwestern University's NUANCE Center, which has received support from the SHyNE Resource (NSF Grant No. ECCS-2025633), the IIN, and Northwestern's MRSEC program (NSF Grant No. DMR-1720139). Support is acknowledged from the Northwestern-Fermilab Center for Applied Physics and Superconducting Technologies (CAPST). Support is also acknowledged by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under Contract No. DE-SC0014664.
ASJC Scopus subject areas
- General Materials Science
- Physics and Astronomy (miscellaneous)