H-Mediated magnetic interactions between layers in a 2D Mn-II-dicyanamide polymer: neutron diffraction, DFT, and quantum Monte Carlo calculations

We report neutron-diffraction investigations of the quasi-2D Mn-II(dca)(2)(pym)(H2O) (pym = N2C4H4) compound, where high-spin Mn-II ions are bridged by dicyanamide anions, [N(CN)(2)](-) (herein abbreviated dca). Inside the layers, Mn2+ ions are connected by single or double dca bridges. The magnetic...

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Detalhes bibliográficos
Autores: Gillon, Beatrice, Hammerschmied, Albert, Gukasov, Arsen, Cousson, Alain, Cauchy, Thomas, Ruiz Sabín, Eliseo, Schlueter, John A., Manson, Jamie L.
Formato: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2018
País:España
Recursos:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/154801
Acesso em linha:https://hdl.handle.net/2445/154801
Access Level:acceso abierto
Palavra-chave:Lligands
Estructura cristal·lina (Sòlids)
Teoria del funcional de densitat
Propietats magnètiques
Metalls de transició
Ligands
Layer structure (Solids)
Density functionals
Magnetic properties
Transition metals
Descrição
Resumo:We report neutron-diffraction investigations of the quasi-2D Mn-II(dca)(2)(pym)(H2O) (pym = N2C4H4) compound, where high-spin Mn-II ions are bridged by dicyanamide anions, [N(CN)(2)](-) (herein abbreviated dca). Inside the layers, Mn2+ ions are connected by single or double dca bridges. The magnetic phase diagram was established by neutron diffraction on a single crystal. In the low-field phase, the Mn-II ions are antiferromagnetically ordered in the layers, with moments nearly parallel to the c axis, and the layers are antiferromagnetically coupled. The spin-flop phase corresponds to ferromagnetic coupling between the antiferromagnetic layers, in which the Mn-II moments are nearly perpendicular to the c axis. The induced spin-density distribution in the paramagnetic phase, determined by polarized neutron diffraction, visualizes the superexchange pathways through the dca ligands within the layers and through H bonding between neighboring layers. The theoretical spin density obtained by bidimensional periodic DFT calculations is compared with the experimental results. Furthermore, quantum Monte Carlo simulations have been performed to compare the DFT results with experimental susceptibility measurements.

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