Abstract: Time-of-flight mass spectra of both positive and negative ions were recorded on a home-made instrument by laser ablation of YBa_2Cu_3O_(7-x) superconducting material. Among the observed cations, Ba~+ has the highest intensity, and Cu~- for anions. In addition, three seires of oxides clusters cations of very broad mass range were observed, with compositions of BaYO_2(Y_2O_3)_n, Ba_2YO_3(Y_2O_3)_n and BaCuYO_3(Y_2O_3)_n. The experimental results were disscused and attributed to the interactions among consisting elements. As comparision, the samples of the CuO, Y_2O_3 and BaO as well as their mixture have also been studied in the same experimental condition.

Key words: Metal oxides, High temperature superconducting material, Laser plasma mass spectrometry