Thermodynamic and Transport Properties of CeMg2Cu9 under Pressure

TL;DR

This study investigates how pressure influences the magnetic, thermodynamic, and transport properties of the antiferromagnetic Kondo compound CeMg2Cu9, revealing a quantum critical point at 2.4 GPa.

Contribution

It provides detailed experimental data on pressure effects in CeMg2Cu9, highlighting the evolution of magnetic ordering and Kondo behavior under pressure.

Findings

Neel temperature initially increases then decreases with pressure.

Quantum critical point occurs at 2.4 GPa where magnetic order vanishes.

Pressure causes merging of Kondo-related resistivity peaks.

Abstract

We report the transport and thermodynamic properties under hydrostatic pressure in the antiferromagnetic Kondo compound CeMg2Cu9 with a two-dimensional arrangement of Ce atoms. Magnetic specific heat Cmag(T) shows a Schottky-type anomaly around 30 K originating from the crystal electric field (CEF) splitting of the 4f state with the first excited level at \Delta_{1}/kB = 58 K and the second excited level at \Delta_{2}/kB = 136 K from the ground state. Electric resistivity shows a two-peaks structure due to the Kondo effect on each CEF level around T_{1}^{max} = 3 K and T_{2}^{max} = 40 K. These peaks merge around 1.9 GPa with compression. With increasing pressure, Neel temperature TN initially increases and then change to decrease. TN finally disappears at the quantum critical point Pc = 2.4 GPa.