Data for Determining the anisotropy and exchange parameters of polycrystalline spin-1 magnets

The results obtained from the thermodynamic measurements are checked against electron-spin resonance and neutron diffraction. We also present a density functional method, which incorporates spin–orbit coupling to estimate the size of the anisotropy in [Ni(H2O)2(pyrazine)2](BF4)2.<br><br>Raw data files in .dat format underpinning figs in related publication. Each .dat file is named corresponding to the fig. (e.g. Fig6a.dat corresponds to Fig 6a in the article) Data for Fig. 6a, Fig. 8a, Fig. 10a and Fig. 10a insert shows temperature in kelvin (column 1) and molar susceptibility (column 2).

Data for Fig. 6b is made up of 4 pairs of columns corresponding to applied field in tesla and magnetisation in Bohr magnetons per formula unit for measurements at given intervals. Data for Fig. 6c, Fig. 8d and Fig. 11a shows temperature in kelvin (column 1) and total heat capacity divided by temperature (column 2). Data for Fig. 6d and 8e is made up of pairs of columns corresponding to temperature in kelvin and magnetic heat capacity at given measurements.

Data for Fig. 7a is made up of 7 pairs of columns corresponding to applied field in tesla and ESR transmission intensity in arbitrary units for given measurements. Data for Fig. 7b is made up of 4 pairs of columns corresponding to the same domain with given simulated measurements. Data for Fig. 7c is made up of pairs of columns corresponding to field in tesla and frequency in GHz for observed resonances observed in ESR data.

Columns 1-8 are fitted to a Hamiltonian. Columns 9-10 contain field for off-axis resonances that weren't fitted. Further columns 11-26 show the resultant simulation from the fit to above Hamiltonian.

Data for Fig. 8b and Fig. 10c is made up of 4 pairs of columns corresponding to field in tesla and magnetisation in Bohr magnetons per formula unit for field sweeps at given measurements. Data for Fig. 8c shows field in tesla (column 1) and dM/dH data in arbitrary units (column 2). Data for Fig. 10b shows temperature in kelvin (column 1) and d(Chi*T)/dT data (column 2).

Data for Fig. 10d is made up of 4 pairs of columns corresponding to field in tesla and dM/dH in arbitrary units for field sweeps at given measurements. There is also insert data for 10d which shows temperature in kelvin (column 1) and d2MdH2 data (column 2). Data for Fig. 11b shows temperature in kelvin (column 1), entropy (column 2), upper bound on entropy (column 3) and lower bound on entropy (column 4).

Data for Fig. 11c is made up of 10 pairs of columns corresponding to temperature in kelvin and magnetic heat capacity for measurements at given measurements. There is also insert data for 11c. Fig 12a shows Muon-spin relaxation spectra and fits provided for data shown.

Columns are explained in the file headers. Data for Fig. 12b shows Neutron powder diffraction data. Difference data shows Neutron powder diffraction difference curve between data and fit.

Inset calculations for left and right show Neutron powder diffraction calculation in insets of fig. 12b. In all cases, left column gives d spacing in units Angstrom, and right column gives intensity, in arbitrary units. Data for Fig. 12c shows moment size (column 2, arbitrary units) and associated error (column 3) vs temperature (column 1, kelvin).