Synthesis of high-Tc superconductor compposed of Sr, Cu and O and enhancement of Tc by ordering of apical O atoms

由Sr、Cu和O组成的高温超导体的合成以及通过顶端O原子的有序化提高Tc

基本信息

批准号：
22340094
负责人：
UCHIDA Shin-ichi
金额：
$ 7.9万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2010
资助国家：
日本
起止时间：
2010 至 2012
项目状态：
已结题

项目摘要

Sr2CuO3+〓 (Sr2CuO4-y) is an amazing copper oxide (cuprate) superconductor with the K2NiF4 crystal structure identical to the first high-Tc cuprate La2-xBaxCuO4 (La214) but with the superconducting critical temperature Tc well exceeding the liquid nitrogen boiling temperature 77 K. The structure is simlest among the known cuprates with only one CuO2 plane in a unit cell, wheras Tc is highest among the single-layer cuprates. This compound has advantages for application; (1) it is composed of least number of elements, Sr, Cu, and O, (2) it does not contain toxic element nor rare-earth element, (3) it is free from atomic disorder, in which dopant atom is oxygen itself located at the apical site, as shown in our preceding study, and hence the dopant atoms are easy to order by low-temperature annealing. However, a difficulty is to synthesize single-phase material, since the apical-O atoms order in various forms with different Tc’s .which prevents physical characterization of this compound.In … More the present study, we synthesized polycrystalline materials under high presuures and hightemperatures, and post annealed them in order to promote ordering of dopant apical oxygen atoms. By optimizing the synthesis and annealing conditions, and by partial substitution of Ba for Sr, we succeeded in enhancing Tc to 98.5 K for Sr2-xBaxCuO3+〓 which is highest so far recorded in single-layer cuprates, and even higher than Tc’s for bilayer YBCO and Bi2212. On the other hand, the volume fraction of this highest-Tc phase never reached 100 %. Then, we started an endeavor to transform a single crystal . Sr2CuO3 composed of CuO chain array to a crystal with K2NiF4 structure composed of CuO2 planes. This transformation was successfully done under high pressure, high temperature, and high oxidizationatmosphere. At the moment, Tc is around 40 K and the size of the crystal is about 100 〓m, but the superconducting volume fraction is certainly 100 %, and the crystal size is large enough to measure resistivity both in-plane and c-axis directions. Now, we stand on the starting point to investigate physical properties of this amazing high-Tc superconducting material. Less

SR2CUO3+〓（SR2CUO4-Y）是一种惊人的氧化铜（铜）超导体，具有K2NIF4晶体结构与第一个高-TC cuprate La2-Xbaxcuo4（LA214）相同CUO2平面在单位电池中，而TC在单层铜岩中最高。该化合物具有应用的优势； (1) it is composed of least number of elements, Sr, Cu, and O, (2) it does not contain toxic element nor rare-earth element, (3) it is free from atomic disorder, in which dopant atom is oxygen itself located at the apical site, as shown in our preceding study, and hence the dopant atoms are easy to order by low-temperature annealing.但是，一个困难的是综合单相材料，因为顶端原子原子以各种形式具有不同的TC。这阻止了这种化合物的物理表征。通过优化合成和退火条件，通过将BA部分取代为SR，我们成功地将TC提高到98.5 K的SR2-XBAXCUO3+〓，迄今为止，它在单层丘比特中的记录最高，甚至比TC高于TC，甚至比TC高于TC的BiLayer YBCO和Bi2212。另一方面，此最高-TC相的体积分数从未达到100％。然后，我们开始了一项努力，以转化一个晶体。 SR2CUO3由CuO链阵列组成，该阵列与K2NIF4结构由CuO2平面组成。这种转化成功地在高压，高温和高氧化剂层下进行。目前，TC约为40 K，晶体的大小约为100 m，但是超导体积分数肯定是100％，晶体尺寸足够大，可以测量平面内和C轴方向。现在，我们站在起点，研究这种惊人的高-TC超导材料的物理特性。较少的

项目成果

期刊论文数量（0）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Cation effects in new superconductors Sr<_2-_x>Ba_xCuO<_3+_δ>

新型超导体Sr<_2-_x>Ba_xCuO<_3+_δ>中的阳离子效应

DOI：
发表时间：
2010
期刊：
Physica C
影响因子：
1.7
作者：
Hirofumi Sakakibara;Hidetomo Usui;Kazuhiko Kuroki;Ryotaro Arita;Hideo Aoki;Takahiro Misawa and Masatoshi Imada;松田康弘,中村俊幸,道村真司,稲見俊哉,金道浩一,海老原孝雄,網塚浩;W.B.Gao
通讯作者：
W.B.Gao

Intra-unit-cell electronic nematicity of the high-T_c copper-oxide pseudogap state

高T_c氧化铜赝能隙态的晶胞内电子向列性