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

doi:10.1103/PhysRevLett.124.117203

Quantum Critical Point in the Itinerant Ferromagnet Ni_{1-x}Rh_{x}

Phys Rev Lett. 2020 Mar 20;124(11):117203. doi: 10.1103/PhysRevLett.124.117203.

Authors

C-L Huang¹, A M Hallas^{1

2}, K Grube³, S Kuntz³, B Spieß^{1

4}, K Bayliff⁵, T Besara^{6

7}, T Siegrist^{6

8}, Y Cai⁹, J Beare⁹, G M Luke^{9

10}, E Morosan¹

Affiliations

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

PMID: 32242686
DOI: 10.1103/PhysRevLett.124.117203

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}.