Inelastic neutron scattering to very high pressures

Progress in high-pressure and neutron scattering methods has recently allowed measurements of phonon dispersion curves of simple solids at high pressures to 10 GPa. In this technique single crystals of 10–25 mm³ volume are compressed by the Paris-Edinburgh cell and the phonon frequencies are measured on high-flux triple axis spectrometers. Detailed studies of the lattice dynamics of low-compressible systems are feasible, including measurements of mode Grüneisen parameters, elastic constants, and precursor effects of phase transitions. We describe the experimental set-up and illustrate its potential by results on semiconductors (Ge and GaSb) and metals (Fe and Zn) obtained at the LLB (Saclay) and ILL (Grenoble) reactor sources. This revised version was published online in July 2006 with corrections to the Cover Date.