2026-10-12T09:43:43Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33736504 2026-09-14T12:27:09Z portal_1197 item_type_3 month_year_09_2026

Data for Combining microscopic and macroscopic probes to untangle single-ion anisotropy and exchange energies in a S = 1 quantum antiferromagnet Jamie Brambleby (1422472) Jamie L. Manson (1409152) Paul Goddard (564595) Matthew B. Stone (1455946) Roger D. Johnson (1549621) Pascal Manuel (1549624) Jacqueline A. Villa (11873124) C. M. Brown (2010895) Helen Lu (6667484) Chikara Shalinee (24875194) Vivien S. Zapf (1411666) Saul H. Lapidus (1453873) Rebecca Scatena (1472455) Piero Macchi (1422475) Yu-sheng Chen (434802) Lai-Chin Wu (1712800) John Singleton (1411675) Antiferromagnetism Anisotropy Quantum theory Nuclear spin Migrated from ePrints The magnetic ground state of the quasi-one-dimensional spin-1 antiferromagnetic chain is sensitive to the relative sizes of the single-ion anisotropy (D) and the intrachain (J) and interchain (J') exchange interactions. The ratios D/J and J'/J dictate the material's placement in one of three competing phases: a Haldane gapped phase, a quantum paramagnet and an XY-ordered state, with a quantum critical point at their junction. We have identified [Ni(HF)2(pyz)_2]SbF6, where pyz = pyrazine, as a rare candidate in which this behavior can be explored in detail. Combining neutron scattering (elastic and inelastic) in applied magnetic fields of up to 10~tesla and magnetization measurements in fields of up to 60~tesla with numerical modeling of experimental observables, we are able to obtain accurate values of all of the parameters of the Hamiltonian [D = 13.3(1)~K, J = 10.4(3)~K and J' = 1.4(2)~K], despite the polycrystalline nature of the sample. Density-functional theory calculations result in similar couplings (J = 9.2~K, J' = 1.8~K) and predict that the majority of the total spin population resides on the Ni(II) ion, while the remaining spin density is delocalized over both ligand types. The general procedures outlined in this paper permit phase boundaries and quantum-critical points to be explored in anisotropic systems for which single crystals are as yet unavailable.<br><br>Data for Phys. Rev. B 95, 134435 (2017) resulting from the UK effort FigS2a.dat Neutron powder diffraction spectrum at 20 K FigS2b.dat Neutron powder diffraction spectrum at 1.5 K Fig2c.dat Ordered Magnetic moment vs. temperature Fig3.dat Heat capacity vs. temperature; Fig4a.dat Powder magnetization (M) of [Ni(HF2)(pyz)2]SbF6 vs. applied magnetic field (\mu_{0}H) Fig4b.dat Powder differential susceptibility (dM/dH) of [Ni(HF2)(pyz)2]SbF6 vs. applied magnetic field (\mu_{0}H) at 0.6 K Fig 4c.dat Powder differential susceptibility (dM/dH) of [Ni(HF2)(pyz)2]SbF6 vs. applied magnetic field (\mu_{0}H) Fig5.dat Applied Magnetic Field (\mu_{0}H) vs. temperature phase diagram of [Ni(HF2)(pyz)2]SbF6 Fig9a Linear susceptibility vs. temperature for a powdered sample of [Ni(HF2)(pyz)2]SbF6, recorded in a quasistatic applied magnetic filed of \mu_{0}H = 0.1 T. 2018-03-03T00:00:00Z Dataset Dataset 10.82444/warw.33736504.v1 https://figshare.com/articles/dataset/Data_for_Combining_microscopic_and_macroscopic_probes_to_untangle_single-ion_anisotropy_and_exchange_energies_in_a_S_1_quantum_antiferromagnet/33736504 CC BY 4.0