Quantum Critical Point in the Itinerant Ferromagnet ${\mathrm{Ni}}_{1\ensuremath{-}x}{\mathrm{Rh}}_{x}$

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, and E. Morosan

Phys. Rev. Lett. 124, 117203 – Published 19 March 2020

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 $α_{V} / T$ and the Grüneisen ratio $Γ = α_{V} / C_{el}$ both diverge logarithmically in the low temperature limit, further indication of a ferromagnetic quantum critical point in ${Ni}_{1 - x} {Rh}_{x}$ .

Received 15 January 2020
Accepted 26 February 2020

DOI:https://doi.org/10.1103/PhysRevLett.124.117203

Physics Subject Headings (PhySH)

Ferromagnetism Quantum criticality Quantum phase transitions

Disordered alloys

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

C.-L. Huang ^1,*, A. M. Hallas^1,2, K. Grube³, S. Kuntz³, B. Spieß^1,4, K. Bayliff⁵, T. Besara ^6,7, T. Siegrist^6,10, Y. Cai⁸, J. Beare⁸, G. M. Luke ^8,9, and E. Morosan¹

¹Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
²Department of Physics and Astronomy and Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
³Institute for Quantum Materials and Technologies, 76021 Karlsruhe, Germany
⁴Department of Chemistry, Johannes Gutenberg-University Mainz, 55131 Mainz, Germany
⁵Department of Chemistry, Rice University, Houston, Texas 77005, USA
⁶National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
⁷Department of Physics, Astronomy, and Materials Science, Missouri State University, Springfield, Missouri 65897, USA
⁸Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
⁹TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
¹⁰FAMU-FSU College of Engineering, Tallahassee, Florida 32310, USA