氧含量对Fe掺杂YBCO体系中载流子局域化与离子团簇效应的影响  

Effect of oxygen content on carrier localization and ion-cluster effect for the Fe-doped YBCO system

作　　者：李领伟[1] 曹世勋[1] 黎文峰[1] 刘芬[1] 池长昀[1] 敬超[1] 张金仓[1] 

机构地区：[1]上海大学物理系,上海200444

出　　处：《物理学报》2005年第8期3839-3844,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10274049);上海市教育委员会"曙光"计划(批准号:03SG35);上海市教育委员会重点学科建设项目资助的课题~~

摘　　要：对YBa2Cu3-xFexOy(x=0·0,0·1,0·2)和YBa2Cu2·8Fe0·2Oy(y=7·05—6·53)系列样品的氧含量、霍尔系数和超导电性进行了系统的研究.结果表明,氧含量的变化对样品中载流子的输运和转移及超导电性有重要影响;适当增加氧含量可以减缓Cu(1)位元素替代对超导转变温度Tc的抑制;在CuO2面上参与输运的载流子(空穴)浓度是影响样品超导电性的关键因素.从电荷转移模型出发,结合掺杂离子引起的载流子局域化和离子团簇效应,对载流子浓度随掺杂量和氧含量的变化从微观结构方面进行了讨论.元素替代量的增加或者氧含量的降低(相同替代量的情况下)都将导致Cu-O链区的有效氧空位增多,导致替代元素的离子团簇效应和载流子局域化效应趋于增强,这是引起参与输运的载流子浓度下降,进而导致Tc降低的主要原因.The oxygen content, Hall coefficient and super-conductivity are systematically studied on YBa2 Cu3-x Fe-x O-y ( X = 0. 0, 0. 1, 0. 2) and YBa2 Cu-2.8 Fe-0.2 O-y ( y = 7.05-6.53) systems. The results show that oxygen content has a great influence on the transport and transfer of carriers and the superconductivity of the samples, the suppression of T-c caused by Cu ( 1) site substitution could be weakened by the increase of oxygen content to some extent. The carrier (holes) density in CuO2 plane plays a key role in affecting the superconductivity. Based on the charge transfer model, and considering the carrier localization and ion-cluster effect resulting from Fe substitution on Cu( 1) site, we have discussed the change of carrier density caused by the oxygen content and Fe doping concentration. It proves that with the increase of Fe doping concentration or the decrease of oxygen content (for the same doping concentration), the efficient oxygen vacancy increases, which enhances the ion-cluster effect and the carrier localization effect, resulting in the decrease of carrier density that participats in superconducting transport in the CuO2 plane, and accordingly, the decrease of T-c.

关 键 词：团簇效应 氧含量 局域化 YBCO体系 载流子浓度 Fe 超导电性 超导转变温度 CuO2面 元素替代 电荷转移 掺杂离子 微观结构 替代量 样品 系数和 输运 氧空位 掺杂量 Tc 空穴 链 

分 类 号：O511[理学—低温物理]