Lightly stuffed pyrochlore structure of single-crystalline Yb2Ti2O7 grown by the optical floating zone technique

Abstract

Recent neutron scattering and specific heat studies on the pyrochlore Yb2Ti2O7 have revealed variations in its magnetic behavior below 265mK. In the best samples, a sharp anomaly in the specific heat is observed at T=265mK. Other samples, especially single crystals, have broad features in the specific heat which vary in sharpness and temperature depending on the sample, indicating that the magnetic ground state may be qualitatively different in such samples. We performed detailed comparisons of the chemical structure of a pulverised single crystal of Yb2Ti2O7, grown by the floating zone technique, to a sintered powder sample of Yb2Ti2O7. Rietveld refinements of neutron powder diffraction data on these samples reveal that the crushed single crystal is best described as a "stuffed" pyrochlore, Yb2(Ti(2-x)Yb(x))O7-(x/2) with x = 0.046(4), despite perfectly stoichiometric starting material. Substituting magnetic Yb3+ on the non-magnetic Ti4+ sublattice would introduce random exchange bonds and local lattice deformations. These are expected to be the mechanism leading to of the variation of the delicate magnetic ground state of Yb2Ti2O7. Determination of the cubic cell length, a, could be useful as a method for characterizing the stoichiometry of non- pulverised single crystals at room temperature.

11 pages, 7 figures. Some additional discussion. Now published in Phys. Rev. B

References in corpus (8)

• Is the Yb2Ti2O7 pyrochlore a quantum spin ice?
• Rods of Neutron Scattering Intensity in Yb2Ti2O7: Compelling Evidence for Significant Anisotropic Exchange in a Magnetic Pyrochlore Oxide
• Structural distortion and the spin liquid state in Tb2Ti2O7
• Stuffed Rare Earth Pyrochlore Solid Solutions
• Field Induced Order and Spin Waves in the Pyrochlore Antiferromagnet Tb2Ti2O7
• Specific Heat of the Dilute Ising Magnet LiHo${}_x$Y${}_{1-x}$F${}_4$
• Local Susceptibility of the Yb2Ti2O7 Rare Earth Pyrochlore Computed from a Hamiltonian with Anisotropic Exchange
• Low temperature dynamic freezing and the fragility of ordering in Tb2Sn2O7

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• Magnetic Frustration in Lead Pyrochlores
• Antiferromagnetic Spin Ice Correlations at (1/2,1/2,1/2) in the Ground State of the Pyrochlore Magnet Tb2Ti2O7
• Synthesis, floating zone crystal growth and characterization of the Quantum Spin Ice $\mathrm{P}{\mathrm{r}}_2\mathrm{Z}{\mathrm{r}}_2{\mathrm{O}}_7$ pyrochlore
• Low Energy Electrodynamics of Novel Spin Excitations in the Quantum Spin Ice Yb${}_2$Ti${}_2$O${}_7$
• Comparative studies of low temperature X-ray diffraction experiments on R2Ir2O7 (R = Nd, Eu, and Pr)
• Structural disorder, magnetism, and electrical and thermoelectric properties of pyrochlore Nd2Ru2O7
• Multiferroicity in spin ice: towards a magnetic crystallography of Tb2Ti2O7 in a field
• Incipient Ferromagnetism in Tb2Ge2O7: Application of Chemical Pressure to the Enigmatic Spin Liquid, Tb2Ti2O7
• Magnetic dilution and domain selection in the XY pyrochlore antiferromagnet Er${}_2$Ti${}_2$O${}_7$