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研究了高压Ar气氛中750℃低温下Tl2O分压对Tl2Ba2CaCu2O8超导薄膜相组成及其性能的影响。结果表明采用名义比为Tl1.9Ba2Ca2Cu3Oy的混合物作铊源时,生成的Tl2O分压达到最佳值。在该Tl2O分压下,获得了单相c取向的Tl2Ba2CaCu2O8超导薄膜,其Tc值达到108K;高于该分压时,薄膜中出现Tl2Ca3O6、Tl2O3等杂相,导致膜面粗糙度增大和Tc值下降;低于最佳Tl2O分压,薄膜中生成了Tl2Ba2CaCu2O8和Tl2Ba2Ca2Cu3O10的共生相,导致Tc值下降;而Tl2O分压的进一步降低,则薄膜在铊化中不形成超导相。
The effect of Tl2O partial pressure on the phase composition and properties of Tl2Ba2CaCu2O8 superconducting thin films was investigated in high-pressure Ar atmosphere at 750 ℃. The results show that when the mixture with nominal ratio of Tl1.9Ba2Ca2Cu3Oy is used as the thallium source, the partial pressure of Tl2O generated reaches the optimum value. Tl2Ba2CaCu2O8 superconducting thin film with single-phase c orientation was obtained under the Tl2O partial pressure, and its Tc value reached 108K. Above this partial pressure, Tl2Ca3O6, Tl2O3 and other heterogeneous phases appeared in the film, resulting in the increase of film surface roughness and Tc Value decreased; below the optimal partial pressure of Tl2O, the symbiosis phase of Tl2Ba2CaCu2O8 and Tl2Ba2Ca2Cu3O10 was formed in the film, resulting in the decrease of Tc value; while the partial pressure of Tl2O further decreased, the film did not form superconducting phase during the thalliumization.