Quantum magnetism in the frustrated square lattice oxyhalides YbBi 2 IO 4 and YbBi 2 ClO 4

Journal Article · 25 January 2024 · Physical Review. B

DOI: https://doi.org/10.1103/physrevb.109.014426 · OSTI ID:2283853

Park, Pyeongjae  ^[1]; Sala, G.  ^[1]; Proffen, Th.  ^[1]; Stone, Matthew B.  ^[1]; Christianson, Andrew D.  ^[1]; May, Andrew F. ^[1]

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1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Square-lattice systems offer a direct route for realizing two-dimensional (2D) quantum magnetism with frustration induced by competing interactions. In this work, the square lattice materials YbBi₂IO₄ and YbBi₂ClO₄ were investigated using a combination of magnetization and specific-heat measurements on polycrystalline samples. Specific-heat measurements provide evidence for long-range magnetic order below $$T$$_N = 0.21 K (0.25 K) for YbBi₂IO₄ (YbBi₂ClO₄). On the other hand, a rather broad maximum is found in the temperature-dependent magnetic susceptibility, located at $$T$$_max = 0.33 K (0.38 K) in YbBi₂IO₄ (YbBi₂ClO₄), consistent with the quasi-2D magnetism expected for the large separation between the magnetic layers. Estimation of the magnetic entropy supports the expected Kramers' doublet ground state for Yb³⁺ and the observed paramagnetic behavior is consistent with a well-isolated doublet. Roughly two-thirds of the entropy is consumed above $$T$$_N, due to a combination of the quasi-2D behavior and magnetic frustration. The impact of frustration is examined from the viewpoint of a simplified $$J$$₁-$$J$$₂ square lattice model, which is frustrated for antiferromagnetic interactions. Specifically, a high-temperature series expansion analysis of the temperature-dependent specific-heat and magnetization data yields $$J$$₂/$$J$$₁ = 0.30 (=0.23) for YbBi₂IO₄ (YbBi₂ClO₄). In conclusion, this simplified analysis suggests strong frustration that should promote significant quantum fluctuations in these compounds, and thus motivates future work on the static and dynamic magnetic properties of these materials.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 2283853
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 1 Vol. 109; ISSN 2469-9950
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English