Pressure‐induced anomalous phase transformation in nano‐crystalline dysprosium sesquioxide

The phase transformation in nano‐crystalline dysprosium sesquioxide (Dy₂O₃) under high pressures is investigated using in situ Raman spectroscopy. The material at ambient was found to be cubic in structure using X‐ray diffraction (XRD) and Raman spectroscopy, while atomic force microscope (AFM) showed the nano‐crystalline nature of the material which was further confirmed using XRD. Under ambient conditions the Raman spectrum showed a predominant cubic phase peak at 374 cm⁻¹, identified as F_g mode. With increase in the applied pressure this band steadily shifts to higher wavenumbers. However, around a pressure of about 14.6 GPa, another broad band is seen to be developing around 530 cm⁻¹ which splits into two distinct peaks as the pressure is further increased. In addition, the cubic phase peak also starts losing intensity significantly, and above a pressure of 17.81 GPa this peak almost completely disappears and is replaced by two strong peaks at about 517 and 553 cm⁻¹. These peaks have been identified as occurring due to the development of hexagonal phase at the expense of cubic phase. Further increase in pressure up to about 25.5 GPa does not lead to any new peaks apart from slight shifting of the hexagonal phase peaks to higher wavenumbers. With release of the applied pressure, these peaks shift to lower wavenumbers and lose their doublet nature. However, the starting cubic phase is not recovered at total release but rather ends up in monoclinic structure. The factors contributing to this anomalous phase evolution would be discussed in detail. Copyright © 2010 John Wiley & Sons, Ltd.     

Scattering length density profile of Ni film under controlled corrosion: A study in neutron reflectometry

We report the density depth profile of an as-deposited Ni film and density profile for the same film after controlled electrochemical corrosion by chloride ions, measured by unpolarized neutron reflectometry. The neutron reflectometry measurement of the film after corrosion shows density degradation along the thickness of the film. The density profile as a function of depth, maps the growth of pitting and void networks due to corrosion. The profile after corrosion shows an interesting peaking nature.      

ChemInform Abstract: On Compound Formation of M′O:M2O3. Part 11. Crystal Structure of BaIn2O4.

Single crystals of the title compound, obtained from a melt after reacting intimate mixtures of BaCO₃ and In₂O₃ at 840 °C (12 h), belong to the monoclinic space group P2₁/a with Z=16.     

ChemInform Abstract: High Pressure Phase Transitions in Scheelite Structured Fluoride: ErLiF4.

ErLiF₄ is prepared by solid state reaction of stoichiometric amounts of LiF and ErF₃ (1.     

ChemInform Abstract: Boron Occupied Condensed Clusters in Ta5Ge3By (y ≈ 0.7).

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