Positron annihilation study of Y_1Ba_2Cu_3O_(6+δ)superconducting ceramics
Chen Ang Zhi Yu(Dept. of Phys. , Dept. of Mat. Scl,Engineer. Zhejiang Univ)Li Biaorong Zhang Xuli(Dept. of Solid Sate Electr. , Huazhong Univ. of Sd. and Technology. )Li Xiaohua Wang Shaojie(Dept. of Phys. Wuhan Univ. )
The positron lifetime spectra of Y1Ba2Cu3O6+δ samples with different oxygen contents were measured. The relationship between positron lifeline and the oxygen vacancy in the ceramics was discussed based on the positron annihilation theory. The results indicated that the order-disorder transition of the oxygen filling in Cu(1)-O chains and the orthorhombic-tetragonal structural phase transition can be sensitively reflected by the positron annnihilation spectrum. It is clear that the positron annihilation technique is one of the most effective tools to study the high Tc oxide superconductors.