Field-induced anisotropy in the quasi-two-dimensional weakly anisotropic antiferromagnet [CuCl(pyz)2]BF4

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  • Sungmin Kwon
  • M. Kubus
  • B. Wehinger
  • K. W. Krämer
  • Ch. Rüegg
  • H. M. Rønnow
  • Soonchil Lee

Colleges, School and Institutes


We measured NMR and magnetic susceptibility for the quasi-two-dimensional, weakly XY -like, spin-1/2 square-lattice Heisenberg antiferromagnet [CuCl(pyz)2]BF4 (pyz = pyrazine = N2C4H4) near the critical temperature. The Néel temperature TN and the order-parameter critical exponent β were obtained from the NMR line broadening as a function of temperature. As the applied field strength (H || c) was increased, TN increased and β decreased. This behavior indicates that the field effectively enhanced XY anisotropy. The susceptibility as a function of temperature did not show a clear feature for TN, but showed field-dependent minima below TN for both H || c and H || ab, where minimum features disappeared for μ0H > 2 T.


Original languageEnglish
Article number214403
Number of pages5
JournalPhysical Review B
Issue number21
Publication statusPublished - 3 Jun 2019