Magnetic properties of the layered heavy fermion antiferromagnet CePdGa$_6$

TL;DR

This study investigates the magnetic properties of the layered heavy fermion antiferromagnet CePdGa$_6$, revealing complex magnetic behavior, metamagnetic transitions, and the influence of long-range interactions, with minimal change under moderate pressure.

Contribution

It provides a detailed magnetic phase analysis of CePdGa$_6$, including a proposed CEF scheme and insights into long-range magnetic interactions, which are novel for this compound.

Findings

CePdGa$_6$ orders antiferromagnetically below 5.2 K.

Two metamagnetic transitions observed for fields along the c-axis.

Pressure up to 2.2 GPa has little effect on $T_N$.

Abstract

We report the magnetic properties of the layered heavy fermion antiferromagnet CePdGa$_{6}$, and their evolution upon tuning with the application of magnetic field and pressure. CePdGa$_{6}$ orders antiferromagnetically below $T\rm_{N}$ = 5.2 K, where there is evidence for heavy fermion behavior from an enhanced Sommerfeld coefficient. Our results are best explained by a magnetic ground state of ferromagnetically coupled layers of Ce $4f$-moments orientated along the $c$-axis, with antiferromagnetic coupling between layers. At low temperatures we observe two metamagnetic transitions for fields applied along the $c$-axis corresponding to spin-flip transitions, where the lower transition is to a different magnetic phase with a magnetization one-third of the saturated value. From our analysis of the magnetic susceptibility, we propose a CEF level scheme which accounts for the Ising anisotropy at low temperatures, and we find that the evolution of the magnetic ground state can be explained considering both antiferromagnetic exchange between nearest neighbor and next nearest neighbor layers, indicating the influence of long-range interactions. Meanwhile we find little change of $T\rm_{N}$ upon applying hydrostatic pressures up to 2.2 GPa, suggesting that significantly higher pressures are required to examine for possible quantum critical behaviors.