Deformed spin- 1 2 square lattice in antiferromagnetic NaZnVOPO 4 ( HPO 4 )

Journal Article · 28 July 2022 · Physical Review. B

DOI: https://doi.org/10.1103/physrevb.106.024426 · OSTI ID:1886215

Guchhait, S. ^[1]; Ambika, D. V.  ^[2]; Ding, Qing-Ping  ^[2]; Uhlarz, M. ^[3]; Furukawa, Y.  ^[2]; Tsirlin, A. A.  ^[4]; Nath, R.  ^[1]

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1. Indian Inst. of Science Education and Research, Thiruvananthapuram (India)
2. Ames Lab., and Iowa State Univ., Ames, IA (United States)
3. Helmholtz-Zentrum Dresden-Rossendorf, (Germany). Dresden High Magnetic Field Lab. (HLD-EMFL)
4. Univ. of Leipzig (Germany)

In this work, we report the structural and magnetic properties of a new spin-$$\frac{1}{2}$$ antiferromagnet NaZnVOPO₄(HPO₄) studied via x-ray diffraction, magnetic susceptibility, high-field magnetization, specific heat, and ³¹P nuclear magnetic resonance (NMR) measurements, as well as density-functional band-structure calculations. While thermodynamic properties of this compound are well described by the J₁ – J₂ square-lattice model, ab initio calculations suggest a significant deformation of the spin lattice. From fits to the magnetic susceptibility we determine the averaged nearest-neighbor and second-neighbor exchange couplings of $$\bar{J}$$₁ ≃ – 1.3 K and $$\bar{J}$$₂ ≃ 5.6 K , respectively, resulting in the effective frustration ratio α = $$\bar{J}$$₂ – $$\bar{J}$$₁ ≃ – 4.3 that implies columnar antiferromagnetic order as the ground state. Experimental saturation field of 15.3 T is consistent with these estimates if 20% spatial anisotropy in J₁ is taken into account. Specific heat data signal the onset of a magnetic long-range order at T_N ≃ 2.1 K , which is further supported by a sharp peak in the NMR spin-lattice relaxation rate. The NMR spectra mark the superposition of two P lines due to two nonequivalent P sites where the broad line with the strong hyperfine coupling and short T₁ is identified as the P(1) site located within the magnetic planes, while the narrow line with the weak hyperfine coupling and long T₁ is designated as the P(2) site located between the planes.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: Science and Engineering Research Board (SERB); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 1886215
• Report Number(s): IS-J 10,877; CRG/2019/000960
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 2 Vol. 106; ISSN 2469-9950
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English