Lattice dynamics of a Pd0.90Rh0.10 crystal

Using inelastic neutron scattering, the phonon dispersion relations along the 100], 110] and 111] directions of a single crystal of Pd_0.90Rh_0.10 have been measured at 296K. From these results and phonon data for Pd, the phonon frequency shifts,(q), and the self-energy function, _j (q, _j (q)), have been determined for all branches. The frequency changes exhibit large wave vector and polarization dependence and behave non linearly with the increase concentration of Rh. The seventh neighbour tensor Born-von Kármán model has been fitted to the experimental phonon dispersion curves, and the force constants and elastic constants calculated. Correlations between the phonon anomalies, displayed in the slope ofT ₁ 110] branch, and the structure of the generalized susceptibility function, ₀(q), for Pd were discussed. From which follows the influence of the electron-electron interaction on theT ₁ 110] branch in Pd and Pd-Rh alloys.