Vortex lattice disorder inYBa2Cu3O7−δprobed using

Abstract

β-detected NMR (β-NMR) has been used to study vortex lattice disorder near the surface of the high-TC superconductor YBa2Cu3O 7−δ (YBCO). The magnetic field distribution from the vortex lattice was detected by implanting a low energy beam of highly polarized 8 Li + into a thin overlayer of silver on optimally doped, twinned and detwinned YBCO samples. The resonance in Ag broadens significantly below the transition temperature TC as expected from the emerging field lines of the vortex lattice in YBCO. However, the lineshape is more symmetric and the dependence on the applied magnetic field is much weaker than expected from an ideal vortex lattice, indicating that the vortex density varies across the face of the sample, likely due to pinning at twin boundaries. At low temperatures the broadening from such disorder does not scale with the superfluid density.

Lithium diffusion in spinel Li4Ti5O12 and LiTi2O4Sugiyama1, Umegaki2, Uyama3 et al. 2017Phys. Rev. B203270View full textAdd to dashboardCite

“…[18], the resonance line changes dramatically both in shape and width below T c which is slightly suppressed by the high applied field. The line shape obtained at the lowest T reached (5 K) is asymmetric, as in the case for superconducting NbSe 2 [50], consistent with the inhomogeneous magnetic field of the vortex state [51,52]. Since the superconductivity is not of primary interest here, we simply fit the resonance spectrum phenomenologically with the Voigt profile over the whole temperature range measured.…”

μSR studies of superconductivity in eutectically grown mixed ruthenates

“…40 Successively, by assuming σ sc ∝ λ −2 , a relation valid in a broad range of circumstances, 41 one can obtain λ −2 . A much larger degree of disorder is expected very close to the surface of a superconductor, 42 but most likely this is not the case for our bulk, single-crystal mosaic sample.…”

Search for broken time-reversal symmetry near the surface of superconducting YBa2Cu3OSaadaoui1, Morris2, Salman3 et al. 2011Phys. Rev. BSelf Cite

“…[28][29][30] The HWHM, ∆, of a single Lorentzian fit to both (110) and (001) samples is plotted in Fig. 2.…”