Cation Substitution in Defect Thiospinels: Structural and Magnetic Properties of GaV4-xMoxS8 (0≤x≤4)
Cation Substitution in Defect Thiospinels: Structural and Magnetic Properties of GaV4-xMoxS8 (0≤x≤4)
复制标题
缺陷硫尖晶石中的阳离子取代：GaV4-xMoxS8 (0≤x≤4) 的结构和磁性
DOI：
10.1021/cm071354t
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发表时间：
2007
影响因子：
8.6
通讯作者：
T. Vogt
中科院分区：
文献类型：
--
作者：
A. Powell;Andrew McDowall;I. Szkoda;K. Knight;B. Kennedy;T. Vogt
制备了一类新的非化学计量比材料GaV 4-xMoxS 8（0≤x≤4），并通过高分辨率中子粉末衍射、实验室和同步加速器X射线粉末衍射、热重分析和SQUID磁力仪进行了表征。所有材料在室温下均为立方（F43 m）结构。端元相GaV_4S_8和GaMo_4S_8在低温下表现出菱面体（R3 m）对称性的畸变。高分辨粉末中子衍射结果表明，相变是不完全的，立方相和菱面体相共存。四万磁化率数据表明，在低温下，端元相经历了一个过渡到铁磁状态，其中立方B4 S4团簇内的金属-金属交换相互作用主要是反铁磁的起源。在中间组成（1≤x≤3），立方结构持续到4 K，材料在此温度下保持顺磁性。菱形畸变的抑制可能是B。
A new family of nonstoichiometric materials, GaV4-xMoxS8 (0≤x≤4), has been prepared and characterized by high-resolution neutron powder diffraction, laboratory and synchrotron X-ray powder diffraction, thermogravimetry, and SQUID magnetometery. All materials adopt a cubic (F43m) structure at ambient temperature. The end-member phases GaV4S8 and GaMo4S8 exhibit a distortion to rhombohedral (R3m) symmetry at low temperatures. High-resolution powder neutron diffraction reveals that the phase transition is incomplete and that both cubic and rhombohedral phases coexist below ca. 40 K. Magnetic susceptibility data indicate that at low temperatures, the end-member phases undergo a transition to a ferromagnetic state in which the metal−metal exchange interactions within cubic B4S4 clusters are predominantly antiferromagnetic in origin. At intermediate compositions (1≤x≤3) a cubic structure persists to 4 K, and materials remain paramagnetic to this temperature. The suppression of the rhombohedral distortion may b...