Eur. Phys. J. B 6, 5-11 (1998)
https://doi.org/10.1007/s100510050520

Pressure-induced magnetically ordered Kondo lattice state in YbCu₂Si₂

University of Geneva, DPMC, 24 quai Ernest-Ansermet, 1211 Geneva 4, Switzerland

Corresponding author: ^a khalid.alami-yadri@physics.unige.ch

Received: 29 December 1997
Revised: 7 July 1998
Accepted: 10 July 1998
Published online: 15 November 1998

Abstract

The effect of pressure on the electrical resistivity ρ(T) of several YbCu₂Si₂ samples was investigated up to 25 GPa and for 30 mK < T < 300 K. With increasing pressure the compound crosses from an intermediate valence state to a magnetic Kondo lattice state at a critical pressure P_C ~ 8 GPa. Below P_C, i.e. in the non-magnetic phase, ρ = ρ₀ + AT² is found at very low temperature, indicating the validity of the Fermi liquid description. On approaching the magnetic instability, the A coefficient and the residual resistivity ρ₀ increase strongly. Close to P_C, ρ₀ shows a pronounced maximum due to scattering by lattice defects. The pressure variation of the magnetic resistivity ρ_mag at high temperature is interpreted in the terms of a pressure induced change of the crystal field splitting.