Compositional control of electrical transport properties in the new series of defect thiospinels, Ga1-xGexV4S8-d (0=x=1)
Compositional control of electrical transport properties in the new series of defect thiospinels, Ga1-xGexV4S8-d (0=x=1)
复制标题
新系列缺陷硫尖晶石 Ga1-xGexV4S8-d (0=x=1) 中电传输特性的成分控制
DOI：
10.1016/j.jssc.2009.07.046
复制
发表时间：
2009
影响因子：
3.3
通讯作者：
Szkoda I
中科院分区：
文献类型：
--
作者：
Szkoda I
在密封石英管中加热化学计量混合元素，在高温下合成了一系列新的非化学计量硫化物Ga 1 − xGexV 4S 8 −δ（0≤x≤1; δ≤0.23）。通过X射线粉末衍射、超导量子干涉仪（SQUID）磁测量和电输运性质测量对样品进行了表征。结构分析表明，在整个组合物范围内形成了固溶体，而热重数据显示在四元相中硫的不足高达2.9%。磁性测量表明，端元相GaV 4S 8的铁磁行为在x≤0.7时保持不变;在此组成范围内的样品在低温下的磁化强度显着增加。相比之下，Ga0.25Ge0.75V4S8−δ似乎在约100 °处经历反铁磁有序。一万五所有x ≥ 1的材料都是n型半导体，其电阻率随着Ga含量的减少而福尔斯近6个数量级，而端元相GeV 4S 8 −δ是p型半导体。结果表明，团簇的物理性质主要取决于团簇内V-V相互作用产生的窄带态的电子填充程度。
A new series of non-stoichiometric sulfides Ga1−xGexV4S8−δ(0≤x≤1; δ≤0.23) has been synthesized at high temperatures by heating stoichiometric mixtures of the elements in sealed quartz tubes. The samples have been characterized by powder X-ray diffraction, SQUID magnetometry and electrical transport-property measurements. Structural analysis reveals that a solid solution is formed throughout this composition range, whilst thermogravimetric data reveal sulfur deficiency of up to 2.9% in the quaternary phases. Magnetic measurements suggest that the ferromagnetic behavior of the end-member phase GaV4S8is retained at x≤0.7; samples in this composition range showing a marked increase in magnetization at low temperatures. By contrast Ga0.25Ge0.75V4S8−δappears to undergo antiferromagnetic ordering at ca. 15K. All materials with x≠1 are n-type semiconductors whose resistivity falls by almost six orders of magnitude with decreasing Ga content, whilst the end-member phase GeV4S8−δis a p-type semiconductor. The results demonstrate that the physical properties are determined principally by the degree of electron filling of narrow-band states arising from intracluster V–V interactions.