title: Tunable and switchable dielectric constant in an amphidynamic crystal.
abstract: The inclusion compound [(CH3)2NH2]2[KCo(CN)6] exhibits a marked temperature-dependent dielectric constant and can be considered as a model of tunable and switchable dielectric materials. Crystal structure and solid-state NMR studies reveal a switchable property between low and high dielectric states around 245 K. This originates from an order-disorder phase transition of the system, changing the dynamics of the polar dimethylammonium (DMA) cation. Furthermore, the tuning of the dielectric constant at temperatures below the phase transition point is related to increasing angular pretransitional fluctuations of the dipole moment of DMA.
authors.affiliation: Ordered Matter Science Research Center, Southeast University, Nanjing 211189, P.R. China. zhangwen@seu.edu.cn
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Heng-Yun
authors.initials: HY
authors.lastname: Ye
authors.forename: Robert
authors.initials: R
authors.lastname: Graf
authors.forename: Hans W
authors.initials: HW
authors.lastname: Spiess
authors.forename: Ye-Feng
authors.initials: YF
authors.lastname: Yao
authors.forename: Run-Qiang
authors.initials: RQ
authors.lastname: Zhu
authors.forename: Ren-Gen
authors.initials: RG
authors.lastname: Xiong