【摘要】 用固态反应的方法制备了层状化合物NaxCoO2(0.52x0.8),并系统地研究了化合物的结构和输运性质.研究表明,随着Na含量x的增加,晶胞参数a增大,而晶胞参数c减小并且其数值远小于那些从Na0.77CoO2中用化学方法脱Na制得的样品的晶胞参数.所有的样品都呈现金属特征的输运性质并且电阻率曲线在x=0.68附近达到一个最小值.本工作还发现对于某些样品在某个温度点Tx附近,dρ/dT会出现一个跳变,这一跳变很可能对应于NaxCoO2材料输运性质从钴氧层内输运到三维空间输运的转变.更多还原

【Abstract】 Structure and transport properties of the layered materials Na_x CoO₂ （0.52x0.8） prepared by solid-state reaction have been investigated systematically. With the increase of x, the in-plane lattice parameter a increases, while the lattice parameter c decreases and is much smaller than those samples with Na contents controlled by chemical de-intercalation from Na 0.77 CoO 2 .It is showed that all the samples are metallic but a minimumof electrical resistivity ρis reached around x0.68. A jump in dρ/dT is observed at the temperature T x , which may correspond to the crossover from two to three dimensional electronic transport behavior.更多还原