Magnetic properties of binary alloys Ni_1-xMo_x and Ni_1-yCu_y close to critical concentrations

Jia-Xiang Hsu^1,2*, Rong-Zhu Lin^1,2, En-Pei Liu^3,4, Wei-Tin Chen^2,3,5, Chien-Lung Huang^1,2

¹Department of Physics and Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, Taiwan
²Taiwan Consortium of Emergent Crystalline Materials, National Science and Technology Council, Taipei, Taiwan
³Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
⁴Department of Physics, National Taiwan University, Taipei, Taiwan
⁵Center of Atomic Initiative for New Materials, National Taiwan University, Taipei, Taiwan

* Presenter:Jia-Xiang Hsu, email:oscar881213@gmail.com

The search for the ferromagnetic quantum critical point (FM QCP) has always been a captivating research topic in the scientific community. In pursuit of this goal, we introduced nonmagnetic transition metals to alloy with elemental nickel, and studied the magnetic properties of nickel binary alloys Ni_1-xMo_x and Ni_1-yCu_y as a function of x and y up to the critical concentrations x_cr and y_cr at which the FM transition disappears. T_c－x(y) phase diagrams were constructed via the Arrott–Noakes scaling of magnetization data. An enhanced Sommerfeld coefficient (the value of C/T as T→ 0) is observed near x_cr and y_cr, manifesting the effect of quantum fluctuations. However, the spin glass behavior is identified through the ac magnetic susceptibility measurements. This observation rules out the possibility of the existence of the FM QCP in both systems.

Keywords: Metals and alloys, Spin glasses, Phase transitions, Magnetic measurements, Disordered systems