Effect of growth conditions on the properties and morphology of chemically derived epitaxial thin films of Ba2YCu3O7−x on (001) LaAlO3
Effect of growth conditions on the properties and morphology of chemically derived epitaxial thin films of Ba2YCu3O7−x on (001) LaAlO3
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DOI：
10.1063/1.351172
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发表时间：
1992-02
影响因子：
3.2
通讯作者：
P. McIntyre;M. Cima;John A. Smith;R. Hallock;M. Siegal;J. Phillips
中科院分区：
文献类型：
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作者：
P. McIntyre;M. Cima;John A. Smith;R. Hallock;M. Siegal;J. Phillips
采用金属有机沉积法制备了Ba2YCu3O7-−-x(BYC)外延薄膜。这是一种非原位工艺，需要在潮湿的气氛中进行高温热处理才能生产出化学计量比的BYC薄膜。化学衍生的超导薄膜在低氧分压下晶化时具有高的临界温度和高的电流密度。在2.5×10−4~1×10−3atm氧气炉气氛中，分别在780℃和83 0℃下进行热处理，制备了厚度为70 nm的超导薄膜，其零场临界电流密度在77K时大于5×10 6A/cm2，在92K时为零电阻.随着薄膜厚度的增加，薄膜的超导性能和表面平整度有下降的趋势。这一行为符合微结构模型，该模型认为薄膜是由靠近薄膜/衬底界面的致密的c轴法向BYC板条与上覆的材料组成的。
Epitaxial thin films of Ba2YCu3O7−x (BYC) were prepared on (001) LaAlO3 single‐crystal substrates by metalorganic deposition of metal trifluoroacetate precursors. This is an ex situ process that requires high‐temperature annealing in a humid atmosphere to produce stoichiometric BYC thin films. The chemically derived superconducting films were found to have high critical temperatures and high current densities when crystallized under low‐oxygen partial pressures. Superconducting films of 70 nm thickness with zero‐field critical current densities greater than 5×106 A/cm2 at 77 K and zero resistance at 92 K were prepared by annealing at 780 and 830 °C in 2.5 × 10−4–1 × 10−3 atm oxygen furnace atmospheres. As the film thickness was increased, the superconducting properties and surface smoothness of the films tended to degrade. This behavior was consistent with a microstructural model in which the films are composed of a dense slab of c‐axis normal BYC near the film/substrate interface with the overlying mater...