Absence of discontinuity in the pressure-volume dependence of CeAl₂and CeIn₃

Abstract

X-ray diffraction experiments performed on the Kondo compounds CeAl2 and CeIn3, under both hydrostatic and quasi-hydrostatic conditions, show a continuous behaviour, contrary to previous results on CeAl2. An anomalously low pressure derivative of the bulk modulus is however observed in both systems, leading to a unit-cell volume at 20 GPa about 4.5% smaller than what is expected for a normal trivalent material. These results are compared with those for pure cerium metal and possible interpretations in terms of valence change and compressible Kondo models are discussed.