Quasi-one-dimensional magnetism in the spin-$\frac12$ antiferromagnet BaNa$_{2}$Cu(VO$_{4}$)$_{2}$

Sebin J. Sebastian; K. Somesh; M. Nandi; N. Ahmed; P. Bag; M. Baenitz; B. Koo; J. Sichelschmidt; A. A. Tsirlin; Y. Furukawa; R. Nath

doi:10.1103/PhysRevB.103.064413

paper

Quasi-one-dimensional magnetism in the spin- $\frac{1}{2}$ antiferromagnet BaNa $_{2}$ Cu(VO $_{4}$ ) $_{2}$

arXiv:2101.05120 · doi:10.1103/PhysRevB.103.064413

Abstract

We report synthesis and magnetic properties of quasi-one-dimensional spin- $\frac{1}{2}$ Heisenberg antiferromagnetic chain compound BaNa $_{2}$ Cu(VO $_{4}$ ) $_{2}$ . This orthovanadate has a centrosymmetric crystal structure, $C 2/ c$ , where the magnetic Cu $^{2 +}$ ions form spin chains. These chains are arranged in layers, with the chain direction changing by 62 $^{0}$ between the two successive layers. Alternatively, the spin lattice can be viewed as anisotropic triangular layers upon taking the inter-chain interactions into consideration. Despite this potential structural complexity, temperature-dependent magnetic susceptibility, heat capacity, ESR intensity, and NMR shift agree well with the uniform spin- $1/2$ Heisenberg chain model with an intrachain coupling of $J / k_{B} ≃ 5.6$ K. The saturation field obtained from the magnetic isotherm measurement consistently reproduces the value of $J / k_{B}$ . Further, the $^{51}$ V NMR spin-lattice relaxation rate mimics the 1D character in the intermediate temperature range, whereas magnetic long-range order sets in below $T_{N} ≃ 0.25$ K. The effective interchain coupling is estimated to be $J_{⊥} / k_{B} ≃ 0.1$ K. The theoretical estimation of exchange couplings using band-structure calculations reciprocate our experimental findings and unambiguously establish the 1D character of the compound. Finally, the spin lattice of BaNa $_{2}$ Cu(VO $_{4}$ ) $_{2}$ is compared with the chemically similar but not isostructural compound BaAg $_{2}$ Cu(VO $_{4})_{2}$ .

12 pages, 11 figures, 1 table, Phys. Rev. B (accepted)

Quasi-one-dimensional magnetism in the spin-21​ antiferromagnet BaNa2​Cu(VO4​)2​

Abstract

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Quasi-one-dimensional magnetism in the spin- $\frac{1}{2}$ antiferromagnet BaNa $_{2}$ Cu(VO $_{4}$ ) $_{2}$