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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Diffraction studies of the low-dimensional frustrated magnetism of layered honeycomb and triangular oxidesтезисы доклада
- Авторы: Kurbakov A.I., Kuchugura M.D., Korshunov A.N., Podchezertsev S.Yu, Rodriguez-Carvajal J., Senyshyn A., Zvereva E.A., Nalbandyan V.B.
- Сборник: Book of Abstracts of Moscow International Symposium on Magnetism (MISM-2017)
- Тезисы
- Год издания: 2017
- Место издания: Москва
- Первая страница: 733
- Последняя страница: 733
- Аннотация: Neutron (NPD)and synchrotron (SPD) powder diffraction studies of the magnetic structures of layered oxides Na3Co2SbO6, Li3Ni2SbO6 and Na2Ni2TeO6 with a honeycomb superstructure of magnetic ions,and MSb2O6 (M = Mn, Co, Cu) and MnSnTeO6 with triangularsuperstructure of magnetic ions within layerare presented. AFM type interaction between nearest, second and third nearest neighbors in honeycomb compounds and triangular structureof layers in MSb2O6 and MnSnTeO6can lead to frustration in the magnetic subsystem and the emergence of unusual types of magnetic moments ordering. The crystal structure of Na3Co2SbO6and Li3Ni2SbO6 was described as honeycomb-type monoclinic (C2/m), whereas crystal structure of Na2Ni2TeO6 as honeycomb-type hexagonal (P63/mcm).However, the structure of M2SbO6 and M2TeO6layerscontaining magnetic ions practically identicaland difference consists in the number of alkali metal layers between the honeycomb-type ones and the packing of honeycomb layers along c-axis. High-resolution SPD has allowed us to define the fine distortions of very rigid hexagons,which are slightly different depending on the type of 3d-ions.It is very important because it was possible to expect that primary superexchange interaction via half-occupied Co/Ni eg (dz2, dx2-y2) orbitals to be FM since within mixed-cation layers of Co/Ni and Sb/Te the Co(Ni) -O- Co(Ni) cation-anion angles are close to 90. Hence, there is a delicate balance of competing AFM and FM interactions due to difference in character and sign of exchanges between Co2+(Ni2+) ions within the magnetic layer. All this was confirmed by the NPD data according to which the magnetic structures for all studied honeycomb samples can be considered as zigzag FM chains AFM coupled.However, the zigzag type is different for each compound and depends on the type of 3d-ions, character of the layers stacking and the distance between the layers determining the strength of the rather small but sometimes significant interlayer interaction. Quite recently, MnSb2O6, a magnet with a chiral crystal structure (P321), was predicted to be multiferroic with unique ferroelectric switching mechanism. We have discovered and synthesized a new trigonal (P-31m) form of MSb2O6 (M = Mn, Co, Cu) that is isostructural with MnAs2O6 and differs from the known form MnSb2O6 (P321). Also we investigated MnSnTeO6 with a chiral crystal (and magnetic) structure as a certain analog of chiral MnSb2O6. This is strictly isoelectronic phases.Experimental low-temperature NPD patterns for all samples show additional reflectionsassociated with neutron magnetic scattering AFM nature that appear at temperatures below TN. Common features of spin ordering are described and the reasons resulting in distinctions between them are analysed. Uncovered unusualcommensurate and incommensurate noncollinear spin arrangementslead toreduce the extent of their spin frustration.All neutron results are in perfect agreement with the measurements of temperature dependencies of the magnetic susceptibility and specific heat. Support by RFBR fund according to the research project № 16-02-00360is acknowledged.
- Добавил в систему: Зверева Елена Алексеевна