Title :
YBaCuO thin films on sapphire up to 2-inch-diameter for microwave applications
Author :
Belov, R.K. ; Drozdov, Y.N. ; Gaponov, S.V. ; Gusev, S.A. ; Klimov, A.Yu. ; Kluenkov, E. ; Morozov, K.V. ; Nozdrin, Y.N. ; Parafin, A.E. ; Pavlov, S.A. ; Reznik, A.N. ; Talanov, V.V. ; Varganov, A.V. ; Volodin, B.A. ; Vorobyev, A.K. ; Vysheslavtzev, P.P.
Author_Institution :
Inst. of Phys. & Microstructures, Acad. of Sci., Nizhny Novgorod, Russia
fDate :
6/1/1995 12:00:00 AM
Abstract :
YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCo) thin films on R-plane sapphire up to 5-cm-diam with ZrO/sub 2/:Y (YSZ) buffer layers were fabricated by in-situ off-axis DC magnetron sputtering-and laser ablation. The film DC properties, critical current density (J/sub c/), effective microwave surface resistance (R/sub s/), X-ray data and surface morphology as functions of deposition temperature (T/sub d/) from 600 to 750/spl deg/C were studied. We have found out that the two processes simultaneously and in different ways affect the YBCO layers superconducting properties versus T/sub d/. The results show that films deposited at both ends of T/sub d/ range have equal critical temperatures but their J/sub c/ and R/sub s/ differ up to an order of magnitude. High-homogeneity 5-cm-diam films with J/sub c/>4 MA/cm/sup 2/ and R/sub s/<0.8, m/spl Omega/ at 10 GHz, and 77 K were routinely fabricated under optimum growth conditions. The effective 2 GHz short-dipole antenna and Wilkinson divider were developed and fabricated from the films.<>
Keywords :
X-ray diffraction; barium compounds; critical current density (superconductivity); dipole antennas; electrical conductivity; high-temperature superconductors; microwave antennas; power dividers; pulsed laser deposition; sputter deposition; superconducting microwave devices; superconducting thin films; superconducting transition temperature; surface conductivity; surface topography; yttrium compounds; 10 GHz; 2 GHz; 2 inch; 5 cm; 600 to 750 C; 77 K; Al/sub 2/O/sub 3/; DC magnetron sputtering; DC properties; Wilkinson divider; X-ray data; YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin films; YBa/sub 2/Cu/sub 3/O/sub 7/; YSZ buffer layers; critical current density; critical temperatures; deposition temperature; effective microwave surface resistance; laser ablation; microwave applications; sapphire substrate; short-dipole antenna; surface morphology; Buffer layers; Laser ablation; Sputtering; Superconducting films; Superconducting magnets; Surface morphology; Surface resistance; Transistors; X-ray lasers; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
