SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
UPt3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. U6+ is bonded to twelve equivalent Pt2- atoms to form a mixture of corner and face-sharing UPt12 cuboctahedra. There are six shorter (2.89 Å) and six longer (3.01 Å) U–Pt bond lengths. Pt2- is bonded in a distorted see-saw-like geometry to four equivalent U6+ atoms.
We have used small-angle neutron scattering to determine the vortex lattice phase diagram in the topological superconductor UPt 3 for the applied magnetic field along the crystalline c -axis. A triangular vortex lattice is observed throughout the superconducting state, but with an orientation relative to the hexagonal basal plane that changes with field and temperature. At low temperature, in the chiral B phase, the vortex lattice undergoes a non-monotonic rotation with increasing magnetic field. The rotation amplitude decreases with increasing temperature and vanishes before reaching the A phase. Within the A phase an abrupt ±15° vortex lattice rotation was previously reported by Huxley et al. , Nature 406 , 160-164 (2000). The complex phase diagram may be understood from competing effects of the superconducting order parameter, the symmetry breaking field, and the Fermi surface anisotropy. The low-temperature rotated phase, centered around 0.8 T, reported by Avers et al. , Nature Physics 16 , 531-535 (2020), can be attributed directly to the symmetry breaking field.
This work under the rubrique of Antiferromagnetism and Superconductivity covers significant aspects of the most important and highest quality of superconductors in the class of quantum materials and the influence of magnetism on the superconducting state. These compounds include high temperature superconductors, pnictide iron-based superconductors, and topological superconductors. Special note is given that crystal growth of uranium based superconductors was performed with equipment created at Northwestern University for this purpose using novel ultra-high vacuum, electron-beam, float zone refining and crystal growth, producing the best quality of bulk single crystals of UPt3 in the literature with RRR=1546.