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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

Sr_2CuO_3 + xCuO_4（Sr_2CuO_4-y）是一种具有K_2NiF_4晶体结构的铜氧化物超导体，其超导临界温度Tc远高于液氮沸点77 K，与第一种高Tc铜氧化物La_2-xCuO_4（La_214）相同。该结构是已知的铜酸盐中最简单的，在一个单位晶胞中只有一个CuO 2平面，其中Tc是单层铜酸盐中最高的。该化合物具有应用上的优点：（1）它由最少数量的元素Sr、Cu和O组成，（2）它不含有毒元素和稀土元素，（3）它没有原子无序，其中掺杂原子是氧本身，如我们先前的研究所示，位于顶端位置，因此掺杂原子易于通过低温退火有序化。然而，困难在于合成单相材料，因为顶端-O原子以具有不同Tc的各种形式有序，这妨碍了该化合物的物理表征。 ...更多信息本研究在高温高压下合成了多晶材料，并对其进行了后退火处理，以促进掺杂剂顶端氧原子的有序化。通过优化合成和退火条件，并通过部分取代Sr的Ba，我们成功地提高Tc到98.5 K的Sr 2-xCuO 3 + Sr 2是迄今为止最高的单层铜酸盐，甚至高于双层YBCO和Bi 2212的Tc。另一方面，该最高Tc相的体积分数从未达到100%。然后，我们开始奋进改造单晶。Sr 2CuO 3晶体由CuO链状排列组成，K2 NiF 4晶体由CuO 2平面组成。这一转变是在高压、高温、高氧化气氛下成功完成的。目前，Tc约为40 K，晶体尺寸约为100 μ m，但超导体积分数肯定是100%，晶体尺寸大到足以测量面内和c轴方向的电阻率。现在，我们站在起点上研究这种令人惊叹的高Tc超导材料的物理特性。少

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