Pressure-Induced Structural Phase Transition and Magnetic Fluctuations in CeNi

The pressure-induced structural phase transition and magnetic fluctuations in the intermediate-valence compound CeNi has been investigated by x-ray and neutron scattering techniques. The observed Cmcm → Pnma structural transition is analyzed using density functional theory calculations, which successfully reproduce the ground state volume, the phase transition pressure, and the volume collapse associated with the phase transition. Equations of state for CeNi on both sides of the phase transition are derived and an approximate P-T phase diagram is suggested for P < 8 GPa and T < 300 K. The inelastic neutron scattering study of the dynamic magnetic response of CeNi reveals that the structural transition increases the characteristic energy of magnetic fluctuations due to enhanced Ce 4f - Ni 3d hybridization. At the same time, the inelastic 4f magnetic form factor remains unchanged.