Magnetic states of the Kondo lattice Ce$_2$PdSi$_3$ and their pressure evolution

TL;DR

This study investigates the magnetic properties of the frustrated heavy fermion compound Ce$_2$PdSi$_3$, revealing how magnetic phase transitions evolve under pressure and highlighting the complex interplay of competing magnetic orders and frustration.

Contribution

It provides the first detailed pressure-dependent magnetic phase diagram of Ce$_2$PdSi$_3$, showing unconventional evolution of magnetic states beyond traditional models.

Findings

Two magnetic transitions at ambient pressure: ferromagnetic-like and incommensurate antiferromagnetic.

Pressure suppresses the ferromagnetic-like transition while the antiferromagnetic transition persists.

Magnetic order evolution suggests competing magnetic interactions and geometric frustration.

Abstract

Frustrated Kondo lattices are ideal platforms for exploring unconventional forms of quantum criticality, as well as magnetism and other emergent phases. Here we report the magnetic properties of the candidate frustrated heavy fermion compound Ce$_2$PdSi$_3$, and map their evolution upon applying magnetic fields and hydrostatic pressure. We find that at ambient pressure Ce$_2$PdSi$_3$ exhibits two distinct magnetic phase transitions, a ferromagnetic-like transition at $T_{\mathrm{M1}}=3.8$ K and an incommensurate antiferromagnetic transition at $T_{\mathrm{M2}}=2.9$ K. Upon applying pressure, $T_{\mathrm{M1}}$ is continuously suppressed and becomes undetectable above 4.2 GPa, whereas $T_{\mathrm{M2}}$ increases and remains robust up to at least 7.5 GPa. The observed pressure evolution of magnetic order in Ce$_2$PdSi$_3$ suggests the presence of competing magnetic orders, and cannot be simply encapsulated by the Doniach phase diagram, motivating further investigations for its origin, including discerning the role of geometric frustration.