Chin. Phys. Lett.  2021, Vol. 38 Issue (8): 087101    DOI: 10.1088/0256-307X/38/8/087101
 CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
Ce-Site Dilution in the Ferromagnetic Kondo Lattice CeRh$_6$Ge$_4$
Jia-Cheng Xu1, Hang Su1, Rohit Kumar1, Shuai-Shuai Luo1, Zhi-Yong Nie1, An Wang1, Feng Du1, Rui Li1, Michael Smidman1,2, and Hui-Qiu Yuan1,2,3*
1Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
2Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310058, China
3State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310058, China
 Abstract The heavy fermion ferromagnet CeRh$_6$Ge$_4$ is the first example of a clean stoichiometric system where the ferromagnetic transition can be continuously suppressed by hydrostatic pressure to a quantum critical point. In order to reveal the outcome when the magnetic lattice of CeRh$_6$Ge$_4$ is diluted with non-magnetic atoms, this study reports comprehensive measurements of the physical properties of both single crystal and polycrystalline samples of La$_x$Ce$_{1-x}$Rh$_6$Ge$_4$. With increasing $x$, the Curie temperature decreases, and no transition is observed for $x > 0.25$, while the system evolves from exhibiting coherent Kondo lattice behaviors at low $x$ to the Kondo impurity scenario at large $x$. Moreover, non-Fermi liquid behavior is observed over a wide doping range, which agrees well with the disordered Kondo model for $0.52 \leq x \leq 0.66$, while strange metal behavior is revealed in the vicinity of $x_{\rm c} = 0.26$. Received: 18 June 2021      Editors' Suggestion Published: 02 August 2021 Fund: Supported by the National Natural Science Foundation of China (Grant Nos. 12034017 and 11974306), the National Key R$\&$D Program of China (Grant Nos. 2017YFA0303100 and 2016YFA0300202), and the Key R$\&$D Program of Zhejiang Province, China (Grant No. 2021C01002).