12 research outputs found
Ubiquitous Spin Freezing in the Superconducting State of UTe2
In most superconductors electrons form Cooper pairs in a spin-singlet state
mediated by either phonons or by long-range interactions such as spin
fluctuations. The superconductor UTe is a rare material wherein electrons
are believed to form pairs in a unique spin-triplet state with potential
topological properties. While spin-triplet pairing may be mediated by
ferromagnetic or antiferromagnetic fluctuations, experimentally, the magnetic
properties of UTe are unclear. By way of muon spin rotation/relaxation
(SR) measurements on independently grown UTe single crystals we
demonstrate the existence of magnetic clusters that gradually freeze into a
disordered spin frozen state at low temperatures. Our findings suggest that
inhomogeneous freezing of magnetic clusters is linked to the ubiquitous
residual linear term in the temperature dependence of the specific heat ()
and the low-temperature upturn in versus . The omnipresent magnetic
inhomogeneity has potential implications for experiments aimed at establishing
the intrinsic low-temperature properties of UTe.Comment: 33 pages, 9 figure
Field of first magnetic flux entry and pinning strength of superconductors for rf application measured with muon spin rotation
The performance of superconducting radiofrequency (SRF) cavities used for particle accelerators depends on two characteristic material parameters: field of first flux entry H-entry and pinning strength. The former sets the limit for the maximum achievable accelerating gradient, while the latter determines how efficiently flux can be expelled related to the maximum achievable quality factor. In this paper, a method based on muon spin rotation (mu SR) is developed to probe these parameters on samples. It combines measurements from two different spectrometers, one being specifically built for these studies and samples of different geometries. It is found that annealing at 1400 degrees C virtually eliminates all pinning. Such an annealed substrate is ideally suited to measure H-entry of layered superconductors, which might enable accelerating gradients beyond bulk niobium technology
Ubiquitous spin freezing in the superconducting state of UTe2
UTe2 receives significant attention as it may be an example of a spin-triplet superconductor but many features of this material are still to be fully understood. Here, the authors use muon spin rotation to investigate the existence of low-temperature magnetic clusters in single crystals of UTe2 and discuss the potential relationship with the temperature dependent behaviour of the specific heat