Gd在Ba_2RCu_3O(7+δ)(R=Y,HO)高温超导体表面上引起的化学反应

Gd-Induced Chemical Reaction on the Surface of the High Temperature Superconductor Ba_2RCu_3O_(7+8)(R=Y, Ho)

本文利用X射线光电子谱(XPS)对Gd原子在Ba_2RCu_3O_(7+8)(R=Y, Ho)高温超导体表面上引起的化学反应进行了研究.实验发现,在该超导样品表面上蒸镀的Gd原子被氧化,超导体中对超导特性起重要作的Cu-O链遭到破坏,其中一部分处于Cu^(2+)态的Cu元素被还原,超导体内其它各元素也不同程度地受到了影响.当样品表面上Gd覆盖度达到22A(R=Y)和30A(R=Ho)时。

In this paper, the x-ray photoelectron spectroscopy (XPS) technique is applied to investigate the Gd-induced chemical reactin on the surface of the high temperature superconductors Ba_2RCu_3O_(7+δ) (R=Y,Ho). Experimental results show that Gd leaches oxygen from the near surface region to form the oxide. This destroys the Cu-O chain in the supercond- uctor, which plays an important role for the superconductivity, and reduces part of copper ions in the state of Cu^(2+). This also affects the other ele- ments in the superconductor. The Gd-induced reaction continues until the Gd coverage reaches 22? (R=Y) or 30? (R=Ho).