Pressure effect on magnetic properties of valence fluctuating system Ce(Ni1-xCux)5

Magnetic susceptibility of the isostructural Ce(Ni1-xCux)5 alloys (0 <=x <= 0.9) was studied as a function of the hydrostatic pressure up to 2 kbar at fixed temperatures 77.3 and 300 K. A pronounced pressure effect on susceptibility is found to be negative in sign and nonmonotonously dependent on the Cu content, showing a sharp maximum at x ∼ 0.4. The experimental results are discussed in terms of the valence instability of Ce ion in the studied alloys. For the reference CeNi5 compound the main contributions to χ? and their volume dependence are calculated ab initio within the local spin density approximation, and appeared to be in close agreement with experimental data.