Preparation and characterization of homogeneous YBCO single crystals with doping level near the SC-AFM boundary

Abstract

High-purity and homogeneous YBa 2 Cu 3 O y single crystals with carrier doping level near the AFM-SC boundary have been obtained in the oxygen content range between y = 6.340 and 6.370. The crystals are ortho-II phase at room temperature and undergo the orthorhombic to tetragonal transition at about 140°C. They show sharp superconducting transitions, with T c between 4 and 20 K. T c changes by 0.8 K when the oxygen content y is changed by 0.001, and is also sensitive to annealing conditions near room temperature, due to the dependence of doping on oxygen ordering correlation lengths. Crystals with oxygen content y lower than 6.345 are non-superconducting.

Magnetic Neutron Scattering in Hole-Doped Cuprate Superconductors

“…The magnetic fluctuations in the very underdoped region of the YBCO 6+x diagram have recently been studied in detail due to recent advances in materials preparation. 30,31 The results showed a similar energy lineshape in the inelastic channel to that observed in very underdoped LSCO.…”

Mechanics of individual isolated vortices in a cuprate superconductor

“…4c,d for the cluster size. We find clusters of order 10 vacancies along the Cu-O chains (see Supplementary Information, Discussion S5), large but reasonable for the sample's length of time at room temperature, where oxygen vacancies migrate slowly and cluster 28 . It is also possible that non-Ginzburg-Landau physics affects the core structure 29 , changing details of the pinning-force anisotropy.…”

Evaluation ofCuO2plane hole doping inYBa2Cu3O6+xLiang1, Bonn2, Hardy3 2006Phys. Rev. B375443801View full textAdd to dashboardCite

“…13 Crystals with oxygen content x = 0 were prepared by annealing the crystals at 660˚C under oxygen partial pressure 1 × 10 -5 Pa. Crystals with x between 0.09 and 0.99 were prepared using procedures reported elsewhere. 14,15 The oxygen content was determined by weight analysis 15 to a precision of ±0.002. The chain oxygen ordered ortho-II, ortho-VIII and ortho-III phases were prepared with x = 0.50, 0.67, and 0.75, respectively, by annealing the crystals at 10˚C below the corresponding ordering temperature 16 , 105˚C, 40˚C, and 75˚C, respectively.…”