Magnetovolume effect in Ce(Ni1−xCux)₅ alloys

Abstract

Magnetic susceptibility χ 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 of 77.3 and 300 K, using a pendulum-type magnetometer. A pronounced pressure effect on χ is found to be negative in sign and strongly (non-monotonously) 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 (LSDA), and appeared to be in close agreement with experimental data.