2024/09/08 by Kristin Kliemt, Kliemt, Kristin, Jacintha Banda +15
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Iron-based superconductors research #Magnetic Properties of Alloys #Rare-earth and actinide compounds #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2409.05150
openalex publication_date 2024/09/08 · openalex created_date 2024/10/22 · openalex updated_date 2026/08/01
We report on single crystal growth and physical properties of the quantum critical Kondo-lattice system YbNi4(P1-xAsx)2 with 0≤ x≤ 1 which hosts a ferromagnetic quantum critical point at x ≈ 0.1. We performed measurements of the magnetization, electrical resistivity, thermopower, heat capacity, and resonant X-ray emission spectroscopy. Arsenic substitution leads to a homogeneous increase of the unit-cell volume, with well-defined As-concentrations in large parts of the single crystals. All data consistently show that with increasing x the Kondo temperature increases, while the magnetic anisotropy observed at low x fully vanishes towards x=1. Consequently, at low temperatures, the system shows a crossover from pronounced non-Fermi liquid behaviour for x ≤ 0.2 to a Fermi liquid behavior for x > 0.2 with weak correlations. There is a continuous change in Yb valence from nearly trivalent at low x to a slightly lower value for x = 0.6, which correlates with the Kondo temperature. Interestingly, specific heat measurements at very low temperatures show that C/T strongly increases towards lower T for x = 0.13 and x = 0.2 with a very similar power law. This suggests that in YbNi4(P1-xAsx)2 a quantum critical region rather than a quantum critical point might exist.