Effect of doping and defects in pyrochlore compounds
ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 73 (2017) C1020-C1020
Crystal growth of pyrochlore rare-earth stannates
Journal of Crystal Growth Elsevier 468 (2016) 335-339
Abstract:
We report crystal growth of several rare-earth stannates RE 2 Sn 2 O 7 (RE=Pr, Tb, Ho, Dy, Yb and Lu) using the flux technique. Different combinations of flux were tried, and a Na 2 B 4 O 7 -NaF (1.2:1) mixture was found to be suitable for crystal growth. X-ray diffraction and thermal characterisation data are presented, as well as some initial measurements of magnetic and thermodynamic properties of the crystals. Little effect was observed with changing oxygen content by Sc substitution for Sn.Spin resonance in the superconducting state of Li1−xFexODFe1−ySe observed by neutron spectroscopy
Physical Review B American Physical Society 94 (2016)
Abstract:
We have performed inelastic neutron-scattering measurements on a powder sample of the superconductor lithium iron selenide hydroxide Li1−xFexODFe1−ySe (x ≈ 0.16, y ≈ 0.02, Tc = 41 K). The spectrum shows an enhanced intensity below Tc over an energy range of 0.64 × 2Δ < E < 2Δ, where Δ is the superconducting gap, and has maxima at the wave vectors Q1 ≈ 1.46 and Q2 ≈ 1.97 °A−1. The behavior of this feature is consistent with the spin-resonance mode found in other unconventional superconductors, and in particular strongly resembles the spin resonance observed in the spectrum of another molecular-intercalated iron selenide Li0.6(ND2)0.2(ND3)0.8Fe2Se2. The signal can be described with a characteristic two-dimensional wave-vector (π,0.67π) in the Brillouin zone of the iron square lattice, consistent with the nesting vector between electron Fermi sheets.Crystal growth of the triangular-lattice antiferromagnet Ba3CoSb2O9
Journal of Crystal Growth Elsevier 468 (2016) 345-348
Abstract:
We report growth of large single crystals of the triangular-lattice antiferromagnetic compound Ba3CoSb2O9 by the floating-zone technique in an image furnace. Evaporation of Sb due to its high volatility was controlled by high pressure and addition of excess Sb in the starting materials to compensate for the losses. The crystal quality was analysed using different X-ray techniques, and the magnetic transition temperature was confirmed by magnetization and heat capacity measurements.Coupled commensurate charge density wave and lattice distortion in Na2Ti2Pn2O (Pn = As,Sb) determined by x-ray diffraction and angle-resolved photoemission spectroscopy
Physical Review B American Physical Society 94 (2016)