钾钨青铜K_xWO_3的晶体结构和电输运特性研究  

CRYSTAL STRUCTURE AND ELECTRONIC TRANSPORT PROPERTIES OF POTASSIUM TUNGSTEN BRONZES K_xWO_3

作　　者：郭娟[1] 郜超军[1] 朱志立[1] 杨立红[2] 董成[2] 

机构地区：[1]郑州大学物理工程学院,郑州450001 [2]中国科学院物理研究所北京凝聚态物理国家实验室超导国家重点实验室,北京100190

出　　处：《低温物理学报》2014年第4期270-275,共6页Low Temperature Physical Letters

基　　金：国家自然科学基金(批准号:51302249);河南省教育厅自然科学研究计划项目(批准号:2009B140009)资助的课题~~

摘　　要：以K2WO4、WO3和W粉为原料,用混合微波方法制备了钾钨青铜KxWO3样品.随着名义钾含量x的增加,KxWO3样品的晶体结构由六方(0.20≤x≤0.33)转变为四方(0.50≤x≤0.60).四方相样品均显示金属型导电特性.在六方相样品K0.2WO3中观测到了明显的电荷密度波(CDW)转变,转变温度为265K,其余六方相样品则为半导体型导电特性.在x=0.20不变的条件下,以Ca部分替代K制备了(K1-2 yCay)0.2WO3(名义钙含量y=0.1,0.2,0.3)样品,其主相仍为六方相.当0<y≤0.2时,六方相的晶胞参数a和c随y的增加而增大.从电阻率-温度曲线上可以看出,名义钙含量的变化会影响样品中的CDW转变.The potassium tungsten bronzes Kx WO3 were prepared from K2 WO4, WO3 and W powders using a hybrid microwave method. With the increase of nominal potassium content x, the crystal structure of Kx WO3 transforms from hexagonal （0. 20≤x≤0. 33） to tetragonal （0. 50≤x≤0. 60）. All samples with tetragonal structure show metallic behavior. Samples with hexagonal structure show semiconducting behavior and the charge density wave （CDW） transition is observed in K0.2 WO3 around 265K. The Ca-doped samples （K1-2y Cay ） 0. 2 WO3 （nominal Ca content y=0. 1, 0. 2 and 0. 3） were also prepared and their major phase is still hexagonal. The lattice parameters a and c of samples （Kl-zyCay）0.2WO3 increase when y inreases from 0 to 0. 2. The CDW transition observed from the p-T curves of Ca-doped samples can be influenced by changing the nominal Ca content y.

关 键 词：钾钨青铜 晶体结构 电输运特性 电荷密度波 

分 类 号：O614.121[理学—无机化学]