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arXiv · 2001.05533

Quantum critical point in the itinerant ferromagnet Ni$_{1-x}$Rh$_x$

C. -L. Huang·A. M. Hallas·K. Grube·S. Kuntz·B. Spiess·K. Bayliff·T. Besara·T. Siegrist·Y. Cai·J. Beare·G. M. Luke·E. Morosan
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Abstract

We report a chemical substitution-induced ferromagnetic quantum critical point in polycrystalline Ni$_{1-x}$Rh$_x$ alloys. Through magnetization and muon spin relaxation measurements, we show that the ferromagnetic ordering temperature is suppressed continuously to zero at $x_{crit} = 0.375$ while the magnetic volume fraction remains 100% up to $x_{crit}$, pointing to a second order transition. Non-Fermi liquid behavior is observed close to $x_{crit}$, where the electronic specific heat $C_{el}/T$ diverges logarithmically, while immediately above $x_{crit}$ the volume thermal expansion coefficient $\alpha_{V}/T$ and the Gr\"uneisen ratio $\Gamma = \alpha_{V}/C_{el}$ both diverge logarithmically in the low temperature limit, further indication of a ferromagnetic quantum critical point in Ni$_{1-x}$Rh$_x$.

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C. -L. Huang, A. M. Hallas, K. Grube, S. Kuntz, B. Spiess, K. Bayliff, T. Besara, T. Siegrist, Y. Cai, J. Beare, G. M. Luke, E. Morosan. 2020-01-15. Quantum critical point in the itinerant ferromagnet Ni$_{1-x}$Rh$_x$. https://doi.org/10.1103/physrevlett.124.117203

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