# Indication of Ferromagnetic Quantum Critical Point in Kondo Lattice CeRh$_6$Ge$_4$

## TL;DR

This study presents resistivity measurements under pressure on CeRh$_6$Ge$_4$, revealing a continuous ferromagnetic quantum critical point, which is rare among clean metallic ferromagnets, and suggests its significance in understanding quantum criticality.

## Contribution

It provides evidence of a ferromagnetic quantum critical point in CeRh$_6$Ge$_4$, a rare case where the transition remains continuous under pressure, challenging typical behavior in similar materials.

## Key findings

- Continuous decrease of Curie temperature with pressure
- Observation of non-Fermi liquid behavior near the transition
- Band structure suggests unusual electronic state

## Abstract

We report resistivity measurements under pressure for Kondo-lattice ferromagnet CeRh$_6$Ge$_4$, and present that a quantum ferromagnetic (FM) phase transition is easily achieved. In most clean metallic ferromagnets, a quantum critical point (QCP) at zero field is avoided by changing the FM transition to a discontinuous transition or to an antiferromagnetic transition. In CeRh$_6$Ge$_4$, to the contrary, the Curie temperature of 2.5 K decreases continuously as increasing pressure without any clear signature that the transition changes to first order. The obvious non Fermi liquid behavior is observed in the vicinity of the quantum FM phase transition. The experimental data do not contradict a picture in which CeRh$_6$Ge$_4$ shows the FM QCP at zero field. Band structure calculation suggests the unusual electronic state of CeRh$_6$Ge$_4$ among Ce-based Kondo lattices. CeRh$_6$Ge$_4$ deserves further investigations and will be a key material to understand the matter of the FM QCP.