Spin-phonon coupling and thermodynamic behaviour in YCrOand LaCrO: inelastic neutron scattering and lattice dynamics.

We report detailed temperature-dependent inelastic neutron scattering andlattice dynamics investigation of magnetic perovskites YCrOand LaCrO. The magnetic neutron scattering from the Cr ions exhibits significant changes with temperature and dominates at low momentum transfer regime.calculations performed including magnetic interactions show that the effect of magnetic interactions is very significant on the low- as well as high-energy phonon modes.

Phonons and oxygen diffusion in BiOand (BiY)O.

We report investigation of phonons and oxygen diffusion in BiOand (BiY)O. The phonon spectra have been measured in BiOat high temperatures up to 1083 K using inelastic neutron scattering.calculations have been used to compute the individual contributions of the constituent atoms in BiOand (BiY)Oto the total phonon density of states.

Phonons and Thermal Expansion Behavior of NiSi and NiGe.

We have carried out first principles calculations of the vibrational and thermodynamic behavior in NiSi and isostructural compound NiGe. Phonon density of states has also been measured in NiSi using inelastic neutron scattering techniques. We find that the vibrational spectra of the two compounds are very different, due to the difference in the size and mass of Si and Ge.

New insights into the compressibility and high-pressure stability of Ni(CN)2: a combined study of neutron diffraction, Raman spectroscopy, and inelastic neutron scattering.

Nickel cyanide is a layered material showing markedly anisotropic behaviour. High-pressure neutron diffraction measurements show that at pressures up to 20.1 kbar, compressibility is much higher in the direction perpendicular to the layers, c, than in the plane of the strongly chemically bonded metal-cyanide sheets.

Lattice dynamics and Born instability in yttrium aluminum garnet, Y3Al5O12.

We report lattice dynamics calculations of various microscopic and macroscopic vibrational and thermodynamic properties of yttrium aluminum garnet (YAG), Y3Al5O12, as a function of pressure up to 100 GPa and temperature up to 1500 K. YAG is an important solid-state laser material with several technological applications. Garnet has a complex structure with several interconnected dodecahedra, octahedra and tetrahedra.