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Zingzag antiferromagnetic order and orbitally induced hierarchy of exchange interactions in honeycomb compounds A3M2SbO6 (A=LiNa, Ag; M=Ni, Coтезисы доклада
- Авторы: Zvereva E.A., Stratan M.I., Ushakov A.V., Nalbandyan V.B., Shukaev I.L., Streltsov S.V., Stroppa A., Picozzi S., Jeschke H.O., Valentí R., Vasiliev A.N.
- Сборник: Proceedings of International Symposium on Structure-Property Relationships in Solid State Material (SPSSM 2016), Nante, France, 2016
- Том: 1
- Тезисы
- Год издания: 2016
- Место издания: Institut des Materiaux Jean Rouxel Нант, Франция
- Первая страница: 49
- Последняя страница: 49
- Аннотация: We present a comprehensive experimental and theoretical study of the electronic and magnetic properties of three quasi-two-dimensional (2D) honeycomb-lattice monoclinic compounds A3M2SbO6 (A=Li, Na, Ag; M=Ni, Co). Magnetic susceptibility and specific heat data are consistent with the onset of antiferromagnetic (AFM) long range order, but ab-initio theoretical calculations reveal both antiferromagnetic and ferromagnetic intralayer spin exchange couplings between M2+ ions are present in the honeycomb planes supporting overall zigzag antiferromagnetic quantum ground state for all three compounds (Fig. 1). In addition, it was found that in contrast to A3Ni2SbO6 (A=Li, Na) compounds where antiferro- and ferromagnetic couplings between Ni2+ (S=1) ions occur at relatively equal strength, the ferromagnetic exchange between Co2+ (S=3/2) ions is radically reduced in Ag3Co2SbO6. Our GGA+U calculations show the importance of the orbital degrees of freedom, which maintain a specific hierarchy of exchange interaction for compound with Co. Thus, the strongest antiferromagnetic exchange coupling in Ag3Co2SbO6 was found in the shortest Co-Co pairs and is due to direct and superexchange interaction between the half-filled xz+yz orbitals pointing directly to each other (as shown on right part of Fig.1). The other four out of six nearest neighbor exchanges within the cobalt hexagon are suppressed, since for these bonds active half-filled orbitals turned out to be parallel and do not overlap. Based on the results of magnetic and thermodynamic studies in applied fields, we also propose the magnetic phase diagrams for all new honeycomb-lattice compounds.
- Добавил в систему: Зверева Елена Алексеевна