Properties of Mn2+ and π-Electron Spin Systems Probed by 1H and 13C NMR in the Organic Conductor κ-(BETS)2Mn[N(CN)2]3

Crystals

Oleg M. Vyaselev²  Reizo Kato¹  Hiroshi M. Yamamoto¹  Megumi Kobayashi¹  Leokadiya V. Zorina²  Sergey V. Simonov²  Nataliya D. Kushch³ 

[1] Institute of Physical and Chemical Research (RIKEN), Hirosawa,Wako, Saitama 351-0198, Japan;Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow region, 142432, Russia;Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow region, 142432, Russia;

关键词: organic metals;    π-d interactions;    spin order;    antiferromagnetism;    metal-insulator transition;    NMR;   

DOI  :  10.3390/cryst2020224

来源: mdpi

【 摘 要 】

Properties of the spin systems of the localized 3d Mn²⁺ ions and the conduction π electrons in quasi-two-dimensional organic conductor κ-(BETS)₂Mn[N(CN)₂]₃ were accessed using ¹H and ¹³C NMR in order to find their relation to the metal-insulator transition which occurs at ∼23 K. The transition of the system into the insulating state is shown to be followed by localization of the π spins into a long-range ordered staggered structure of AF type. In contrast, the 3d Mn²⁺ electron spin moments form a disordered tilted structure, which may signify their trend to AF order, frustrated geometrically by the triangular arrangement of Mn in the anion layer. This result suggests that the MI transition in κ-(BETS)₂Mn[N(CN)₂]₃ is not the consequence of the interactions within the Mn²⁺ spins but due to the interactions within the π-electron system itself. Vice versa, it is more likely that the disordered tilted structure of the Mn²⁺ spins is induced by the ordered π-spins via the π-d interaction.

【 授权许可】

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© 2012 by the authors; licensee MDPI, Basel, Switzerland.