Spin glass behavior in frustrated quantum spin system CuAlO with a possible orbital liquid state.

CuAlO is a normal spinel oxide having quantum spin, S  =  1/2 for Cu. It is a rather unique feature that the Cu ions of CuAlO sit at a tetrahedral position, not like the usual octahedral position for many oxides. At low temperatures, it exhibits all the thermodynamic evidence of a quantum spin glass.

The effect of temperature and pressure on the crystal structure of piperidine.

Background: The response of molecular crystal structures to changes in externally applied conditions such as temperature and pressure are the result of a complex balance between strong intramolecular bonding, medium strength intermolecular interactions such as hydrogen bonds, and weaker intermolecular van der Waals contacts. At high pressure the additional thermodynamic requirement to fill space efficiently becomes increasingly important.

Results: The crystal structure of piperidine-d11 has been determined at 2 K and at room temperature at pressures between 0.

A novel isomorphic phase transition in β-pyrochlore oxide KOs2O6: a study using high resolution neutron powder diffraction.

We have carried out adiabatic calorimetric and neutron powder diffraction experiments on the β-pyrochlore oxide KOs(2)O(6), which has a superconducting transition at T(c) = 9.6 K and another novel transition at T(p) = 7.6 K.

Temperature- and pressure-induced proton transfer in the 1:1 adduct formed between squaric acid and 4,4'-bipyridine.

We have applied a combination of spectroscopic and diffraction methods to study the adduct formed between squaric acid and bypridine, which has been postulated to exhibit proton transfer associated with a single-crystal to single-crystal phase transition at ca. 450 K. A combination of X-ray single-crystal and very-high flux powder neutron diffraction data confirmed that a proton does transfer from the acid to the base in the high-temperature form.

Structure and phase behavior of the expanded-metal compound 7Li(ND3)4.

Metal lite: High-resolution neutron powder diffraction data reveals that the body-centered cubic crystal structure of lithium(0)tetraamine transforms to a simple cubic structure below 22 K. The detailed structure determinations will allow new insights into the coupled structural and electronic properties of the lightest metal.