Tl-Ba-Ca-Cu-K-Al-O体系的超导电性

SUPERCONDUCTIVITY IN A TI-Ba-Ca-Cu-K-AI-O SYSTEM

具有Tco>110K的含铊七元素氧化物超导体TlBaCaCuKAlO已由两步固态反应法合成，起始金属离子比组分该体系的超导电性的影响已经研究，实验结果表明，该体系正离子比的铊含量低至0.8时，并没有严重减小Tco值，但是，铊含量低至0.2时超导电性消失，掺入钾和铝两种元素，采用简单的合成工艺，就可获得高Tc超导电性，对于起始名义组分为Tl0.3BaCaCu2K0.5Al0.2Ox的超导体，Tco可达到114K，并具有两个阴显的超导相；2212相和1112相，均属四方晶系，分别具有晶胞参数为σ=5.541A,c=29.081A和α=5.586A,c=19.665A。

Tl-containing septenary oxide with Tco above 110K, TIBaCaCuKAlO system has been prepared by using-two-steps solid-stalereaction. The Infl-uerk of starting cation ratio composition on the superconductivity of TlBa-CaCuKAl system bas been, investigated.The experimental results show that as the con of thelium in cation ratio in this system is decreased to 0.3, does not adver effect the Tco.However, when the content of thallium in it is decreased to and then the superconductivity of TIBaCaCuKAlO system will be lost. The high Tc superconductivity of TlBaCaCuKAl system with lowing thallium content can be obtained by doping both potassium and Aluminium into TlBaCaCuO system in a simple synthetical process.The value of Tco of Tl0.3 BaCaCu2K0.6A10.2Ox is up to 114K.There are two high Tc superconducting phases of 2212 and 1112 in it.Both belongs to the body-centred tetragonal cells. Their lattice parameters are a=5.541A,c=29.018A和a=5.586A, c = l9.665A; respectively.