Magnetic Blocking at 10 K and a Dipolar-Mediated Avalanche in Salts of the Bis(η<sup>8</sup>-cyclooctatetraenide) Complex [Er(COT)<sub>2</sub>]<sup>−</sup>
作者:Katie R. Meihaus、Jeffrey R. Long
DOI:10.1021/ja4094814
日期:2013.11.27
in symmetry, both compounds exhibit slow magnetic relaxation under zero applied dc field with relaxation barriers of ∼150 cm(-1) and waist-restricted magnetic hysteresis. Dc relaxation and dilution studies suggest that the drop in the magnetic hysteresis near zero field is influenced by a bulk magnetic avalanche effect coupled with tunneling of the magnetization. Through dilution with [K(18-crown-6)(THF)2][Y(COT)2]
η(8)的[K(18-crown-6)](+) (1)和[K(18-crown-6)(THF)2](+) (2)盐的结构和磁性报道了-环辛四烯夹心复合物 [Er(COT)2](-)(COT(2-) = 环辛四烯二价阴离子)。尽管对称性略有不同,但这两种化合物在零外加直流场下表现出缓慢的磁弛豫,弛豫势垒为~150 cm(-1) 和腰部限制磁滞。直流弛豫和稀释研究表明,零场附近磁滞的下降受到体磁雪崩效应和磁化隧道效应的影响。通过用 [K(18-crown-6)(THF)2][Y(COT)2] (3) 稀释,这些现象基本上被淬灭,导致开放的滞后回线达到 10 K。重要的是,这代表了迄今为止观察到的单核复合物的最高阻塞温度和任何单分子磁体的第二高阻塞温度。[K(18-crown-6)][Ln(COT)2] (Ln = Sm, Tb, Dy, Ho, Yb) 磁性的综合比较分析表明,仅 [K(18-crown-6)][Ln(COT)2]