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Spin ordering in the mixed-ligand antiferromagnet Mn(dca)2(pyrazine)

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The flexibility offered by molecular-based systems allows us to introduce or replace specific ligands in a material with the aim of radically altering desired structural and magnetic properties. Specifically, Mn(dca)2(pyz) {dca = dicyanamide, [N(CN)2]-; pyz = pyrazine} has a unique interpenetrating ReO3-like lattice. The Mn2+ cations are high-spin (S = 5/2) and the material orders antiferromagnetically below TN = 2.53(2) K. Using neutron powder diffraction we observed a collinear spin structure oriented along the short ac-diagonal of the monoclinic unit cell. Inelastic neutron scattering results show a magnetic excitation at 0.23 meV. The strong dispersion character of this excitation demonstrates that it is related to a low-energy spin wave. Upon warming, the magnon gradually softens and disappears at TN, while critical scattering becomes evident by a broad quasielastic response above TN. The energy of the magnon is consistent with the exchange parameter, J, derived from magnetic susceptibility measurements.

OriginalsprogEngelsk
TidsskriftJournal of Magnetism and Magnetic Materials
Vol/bind260
Udgave nummer3
Sider (fra-til)462-466
Antal sider5
ISSN0304-8853
DOI
StatusUdgivet - 1 apr. 2003
Eksternt udgivetJa

ID: 210118343