Title :
LaAlO3 single crystal for substrate of high temperature superconducting thin films
Author :
Li, Cong-Zhou ; Yang, Wen-Huang ; Hou, De-Sen ; Fan, Hui ; Zhang, Hui-Yun
Author_Institution :
Inst. of Phys., Chinese Acad. of Sci., Beijang, China
Abstract :
A perovskite-like LaAlO3 single crystal was grown by the Czochralski technique. It was used as a substrate for yttrium barium copper oxide (YBaCuO) superconducting films. The best results were obtained using the (001) surface on the pseudocubic LaAlO3 crystals. The low-frequency relative dielectric constant was measured to be 22±0.001, which remained almost the same at microwave frequencies, and the microwave loss tangent was found to be about 7×10-4 at room temperature. The twin diffraction rock angle of this crystal was about 50 s. The many regular parallel stripes seen under X-ray topography observation were ferroelastic domains. Films deposited on the (001) LaAlO3 surface exhibited sharp superconducting transitions at 92.3 K and the critical current densities were about 4.7×106 A/cm2 at 77 K in a zero magnetic field
Keywords :
X-ray diffraction examination of materials; barium compounds; dielectric losses; ferroelasticity; high-temperature superconductors; lanthanum compounds; permittivity; substrates; superconducting thin films; yttrium compounds; LaAlO3; X-ray topography; YBaCuO; critical current densities; dielectric constant; ferroelastic domains; high temperature superconductors; microwave loss tangent; parallel stripes; single crystal; substrate; superconducting transitions; thin films; twin diffraction rock angle; Crystals; Dielectric constant; Dielectric loss measurement; Dielectric measurements; Dielectric substrates; Frequency measurement; Microwave measurements; Superconducting films; Surface topography; Yttrium barium copper oxide;
Conference_Titel :
Applications of Ferroelectrics, 1990., IEEE 7th International Symposium on
Conference_Location :
Urbana-Champaign, IL
Print_ISBN :
0-7803-0190-0
DOI :
10.1109/ISAF.1990.200290
