Frustration-free spatially anisotropic S=1 square-lattice antiferromagnet Ni[SC(NH2)2

Abstract

Magnetism of the S = 1 Heisenberg antiferromagnets on the spatially anisotropic square lattice has been scarcely explored. Here we report a study of the magnetism, specific heat, and thermal conductivity on Ni[SC(NH 2) 2 ] 6 Br 2 (DHN) single crystals. Ni 2+ ions feature an S = 1 rectangular lattice in the bc plane, which can be viewed as an unfrustrated spatially anisotropic square lattice. A long-range antiferromagnetic order is developed at T N = 2.23 K. Below T N , an upturn is observed in the b-axis magnetic susceptibility and the resultant minimum might be an indication for the XY anisotropy in the ordered state. A gapped spin-wave dispersion is confirmed from the temperature dependence of the magnetic specific heat. Anisotropic temperature-field phase diagrams are mapped out and possible magnetic structures are proposed.

High-field magnetization and electronic spin resonance study in the twisted honeycomb lattice α-Mn2V2O7

“…It confirms a magnetic easy axis [001] of the system and implies a stronger AFM interaction along [1 10], which is in agreement with the results of neutron scattering measurement in [32]. In the molecular field model, both the critical fields are related to the exchange field H e and the anisotropic field H a as follows [8,38]:…”

“…In some kagome lattices with small spin values as S = 1/2 is the case, thermal and quantum fluctuations stabilize the √ 3 × √ 3 structure with the help of the next-nearest-neighbor interaction, leading to a highly degenerate, disordered ground state, which can exhibit triplet excitation, devil's staircase in magnetization and quantum magnetic phase transition behaviors in a finite external field [3][4][5][6]. However, unfrustrated systems like square or honeycomb lattice systems may also have frustrating interactions in the presence of antiferromagnetic (AFM) further-neighbor interactions [7,8]. In particular, in the honeycomb lattice, the in-plane anisotropy, interlayer coupling and competing interactions always result in a deviation from the purely two-dimensional XY model [9], modifying the ground state significantly [10].…”

Spatially anisotropic S=1 square-lattice antiferromagnet with single-ion anisotropy realized in a Ni(II) pyrazine- n,n′ -dioxide coordination polymer

“…Thus, Ni(NCS) 2 (pyzdo) 2 adds to the small library of experimental realizations of spatially anisotropic S = 1 square-lattice AFMs with single-ion anisotropy. Aside from the aforementioned NiX 2 (pyz) 2 compounds [5] (of which NiBr 2 (pyz) 2 was reported before [26]), we have also found a recent report on Ni[SC(NH 2 ) 2 ] 6 Br 2 [27], which was shown to have long-range AFM order at T N = 2.23 K, and magnetization data showed a strong magnetic anisotropy, although details of the Hamiltonian parameters are yet to be determined.…”