Symmetry and light stuffing ofHo2Ti2O7, Er2Ti2O7, andYb2Ti2O7characterized by synchrotron x-ray diffraction Academic Article uri icon

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abstract

  • The Ho2Ti2O7, Er2Ti2O7 and Yb2Ti2O7 pyrochlores were studied by synchrotron X-ray diffraction to determine whether the (002) peak, forbidden in the pyrochlore space group Fd-3m but observed in single crystal neutron scattering measurements, is present due to a deviation of their pyrochlore structure from Fd-3m symmetry. Synchrotron diffraction measurements on precisely synthesized stoichiometric and non-stoichiometric powders and a crushed floating zone crystal of Ho2Ti2O7 revealed that the (002) reflection is absent in all cases to a sensitivity of approximately one part in 30,000 of the strongest X-ray diffraction peak. This indicates to high sensitivity that the structural space group of these rare earth titanate pyrochlores is Fd-3m, and that thus the (002) peak observed in the neutron scattering experiments has a non-structural origin. The cell parameters and internal strain for lightly stuffed Ho2+xTi2-xO7 are also presented.

authors

  • Baroudi, Kristen
  • Gaulin, Bruce D
  • Lapidus, Saul H
  • Gaudet, Jonathan
  • Cava, RJ

publication date

  • July 30, 2015