高压下纳米尺寸Sr_2FeMoO_6粉末的结构稳定性和电学特性的研究

The Structural Stability and Electrical Properties of Nanometer-ScaleSr_2FeMoO_6 Polycrystals under High Pressure

采用高分子网络凝胶法,通过控制其化学反应过程,合成了高纯的多晶纳米级粉末Sr2FeMoO6样品A(50nm)和样品B(100nm)。对其在高压下的结构稳定性和电学性质进行了研究,并将样品A和样品B的实验结果与已报道的粒度达微米级的块状Sr2FeMoO6样品C的实验结果进行了对比。在实验测量范围内,样品A(50nm)呈现出最大的体弹模量B0,并在电阻 压力曲线中,电阻下降区域表现出相对较缓的变化率,晶界效应可以用来很好地解释此结果。电学性质测量实验表明,样品在高压下发生了电子结构相变。

Double perovskite structural compounds Sr_2FeMoO_6 powders with grain sizes of 50 nm (sample A) and 100 nm (sample B) have been synthesized using polymer-network gel method.Their structural stabilities and electrical properties under high pressure have been investigated.As compared with the result of bulk sample C with μm grain size obtained before,the sample A shows the largest bulk modulus B_0 among the three and largest pressure region for the drop in the curve of resistance versus pressure.The results can be explained in terms of the effect of large amount grain boundaries in nanometer-scale materials.On the basis of the results of resistance and capacitance versus pressure,it is considered that both samples undergo an electronic structural transition under high pressure.