X-ray and neutron scattering

Abstract:

Single crystals of RE2Ti2O7 (RE=Y, Tb, Dy and Ho) have been grown by the floating-zone technique in an image furnace in a controlled atmosphere. The effect of annealing the crystals in different atmospheres was studied and found to be very important. Small amounts of Y were doped on the Dy site to study its effect on the spin-ice behaviour. Results for the structural parameters obtained by X-ray diffraction and magnetic properties of the crystals are reported. © 2010 Elsevier B.V. All rights reserved.

Abstract:

Single crystals of Na0.8-yAyCoO2 (A=Ca, Sr; y=0.10.3) have been grown using the optical floating-zone method for the first time. We have determined the optimum growth conditions to grow the highest quality single crystals. Columnar growth behavior has been observed for the higher doped samples. The magnetic and structural ordering temperatures of the doped samples were found to vary considerably. Crown Copyright © 2010 Published by Elsevier B.V. All rights reserved.

Abstract:

High-energy x-ray diffraction data from a series of amorphous ZrW 2O8 samples, recovered from a number of different pressures, have been measured and compared with similar data collected from a sample contained within a diamond anvil cell and measured in situ at high pressure. Samples at lower pressures are a mix of crystalline and amorphous phases, whereas those above 7 GPa (both recovered and in situ) appear to be completely amorphous. Although there are only very small changes in the diffraction data from the pure phase samples recovered from different pressures, larger changes are observed in situ as a function of pressure. However, the same structural model can be used to describe all data, albeit using different densities. This strongly suggests that the amorphous phase is undergoing nonreconstructive compression in this pressure range, without fundamental modification of the underlying topology. © 2011 American Physical Society.