Microstructure and microwave properties of YBCO thin films grown on MgO and SrTiO3 by CVD

Autor: Tsutomu Yamashita, H. Kurosawa, K.H. Young, McD. Robinson, H. Suzuki, L. Drabeck, Toshio Hirai, G.V. Negrete, George Grüner
Rok vydání: 1991
Předmět:
Zdroj: Journal of Materials Research. 6:2259-2263
ISSN: 2044-5326
0884-2914
DOI: 10.1557/jmr.1991.2259
Popis: The microstructure and microwave properties of YBa2Cu3O7−δ thin films grown on SrTiO3 (100) and MgO (100) substrates by chemical vapor deposition have been studied. Both 100 GHz cavity measurement of surface resistance and ground plane substitution in a 5 GHz microstrip resonator show that films on SrTiO3 have better microwave properties than those on MgO. Although there are some a-axis grains and secondary phases on the surface, a large fraction of each film on SrTiO3 is epitaxial with its c axis normal to the substrate. The 100 GHz surface resistance of these films is less than copper for temperature ⋚ 82 K, and approaches the detection limit at 10–20 K. For the films on MgO, c-axis grains of different in-plane rotation are found together with some a-axis needle-like grains. The grain boundaries are detrimental to the microwave properties, and the resulting surface resistance at 100 GHz and 10–20 K is about 20 mΩ higher than that of films on SrTiO3.
Databáze: OpenAIRE
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