Nd_(1+x)Ba_(2-x)Cu_3O_(7-δ)超导体的热处理

Heat Treatment of Nd_(1+x)Ba_(2-x)Cu_3O_ (7-δ) Superconductors

通过对Nd1 +xBa2 -xCu3O7-δ的两种样品 (烧结样品和区域熔炼样品 )的XRD谱图分析 ,研究了高温氩气氛下热处理对样品中Nd对Ba的取代值x的影响 ,同时比较了不同样品的Tc 和Jc 值。研究表明 ,氩气下 95 0℃热处理可以减少Nd对Ba的取代 ,Tc 和Jc 都有不同程度的提高。对不同固溶度x值的Nd1 +xBa2 -xCu3O7-δ进行吸氧热处理 ,样品在热处理前后分别作XRD分析。从XRD谱图可以看出 :当x <0 4时 ,样品经吸氧后可以从四方相转变为正交相 ,而当x >0 4时 。

Two kinds of Nd 1+ x Ba 2- x Cu 3O 7- δ , the sintering samples and zone melting samples, were heat treated under pure Ar at 950 ℃. The substitution of Nd for Ba in the Nd 1+ x Ba 2- x Cu 3O 7- δ before and after the heat treatment were investigated by XRD. In order to know the effects of the heat treatment, the T c and J c of samples with the heat treatment and those without the heat treatment by Ar were comparatively studied. The results show that the substitution of Nd for Ba decreases, while T c and J c increase after the treatment under Ar at 950 ℃. The Nd 1+ x Ba 2- x Cu 3O 7- δ samples were oxygenated under pure oxygen at 300 ℃. From the XRD pattern it is found that the sample with x <0 4 can transfer from tetragonal phase to orthorhombic phase after the oxygenation, but the sample with x >0 4 can not make the phase transition even after a long time oxygenation.