用X－射线和电子衍射对合成汞系超导体的预烧样品的研究  

XRD AND ED INVESTIGATIONS OF Ba_2Ca_2Cu_3O_x FOR PREPARATION OF Hg-Ba-Ca-Cu-O SUPERCONDUCTORS

作　　者：吴小山[1] 邵惠民[1] 蒋树声[1] 沈光俊[1] 姚希贤[1] 

机构地区：[1]南京大学固体微结构实验室,中国科技大学结构分析中心,东南大学分析测试中心

出　　处：《低温物理学报》1996年第1期1-10,共10页Low Temperature Physical Letters

摘　　要：在６００℃－９００℃的温度范围内，每间隔１００℃用固态反应技术将按２：２：３的比例混合的ＢａＯ，ＣａＯ及ＣｕＯ的混合物进行烧结．将不同温度和不同反应时间下进行反应的产物通过Ｘ－射线衍射和电子衍射分析．我们得到了一种新相化合物可能具有Ｂａ２Ｃａ２Ｃｕ３Ｏ７的分子式．其结构为四方相，晶格参数确定为ａ＝１．２９４８（２）ｎｍ，ｃ＝０．Abstract The nominal composition of Ba,Ca,Cu,O.(BCCO) was calcined from the simple metal oxides of BaO, CaO and CuO by using the solid-state reaction technique. The calcined temperature was in the range between 600℃ and 800℃ for 24 hours. as well as at 915℃ for the time range between 3 hoursand 60 hours.The structure and the content of each oxide for the prepared samples were characterized by X-ray diffraction(XRD)and electron-diffraction(ED)analysis. A new oxide which mayhave the chemical formula of Ba2Ca2Cu3Ox was detected. XRD patterns show that this oxide has the tetragonal symmetry with the lattice parameters a=1. 2948(2)urn and c = 0. 9156(4)nm angstrom. Based on this oxide(used as precursor)high-quality HgBa2Ca2Cu3O8+δ(Hg-1223 )superconductor was synthesized. The impurity phase of CaHgO2 formed during the synthesis of Hg-1223 may be related tothe CaO phase contained in the precursor. The calcium cuprate Ca2CuO3 wasalso detected in several samples.

关 键 词：电子衍射 超导体 汞系 预烧样品 X射线 

分 类 号：TM263[一般工业技术—材料科学与工程]