To order, or not to order, that is the question: a magnetic quantum phase transition

Chien-Lung Huang^1*

¹Physics, National Cheng Kung University, Tainan, Taiwan

* Presenter:Chien-Lung Huang, email:clh@phys.ncku.edu.tw

Exotic physical properties, arising from quantum mechanical interactions between quasiparticles, emerge near the boundary between magnetic order and disorder phase. In my talk, I will present experimental signatures of two such examples: a compound Sr_1-xCa_xRuO₃ and an alloy Ni_1-xRh_x. Both systems are itinerant ferromagnets. The former exhibits quantum critical scaling of magnetization and specific heat, while the latter shows divergence of thermodynamic properties as the temperature approaches absolute zero. To uncover the ferromagnetic quantum phase transition, on one hand, helps understand the quantum criticality in the disordered limit. On the other hand, it opens a new route, besides its antiferromagnetic counterpart, to search for emergent phenomena near the quantum phase transition, e.g., unconventional superconductivity.

Keywords: Quantum critical point, ferromagnet, disorder