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

1991 ◽  
Vol 6 (11) ◽  
pp. 2259-2263 ◽  
Author(s):  
K.H. Young ◽  
McD. Robinson ◽  
G.V. Negrete ◽  
T. Yamashita ◽  
T. Hirai ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Resistance ◽  
Large Fraction ◽  
Ground Plane ◽  
Chemical Vapor ◽  
Microwave Properties ◽  
Secondary Phases ◽  
Microstrip Resonator ◽  
Cavity Measurement ◽  
5 Ghz

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.

THE EFFECT OF THE INTERACTION BETWEEN THE FILMS AND THE SUBSTRATES ON THE MICROWAVE PROPERTIES Of YBCO THIN FILMS

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3224-3226
Author(s):  
LIBIN SHI ◽  
YUNFEI WANG ◽  
YUYANG KE ◽  
QUANWU WANG ◽  
ZHEN ZHANG ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Resonant Frequency ◽  
Temperature Dependence ◽  
Surface Resistance ◽  
Microwave Properties ◽  
Microwave Surface Resistance ◽  
Microstrip Resonator ◽  
Lower Temperature ◽  
Xrd Patterns

The microwave properties of YBa 2 Cu 3 O 7- x / LaAlO 3 (YBCO/LAO) and YBa 2 Cu 3 O 7- x / MgO (YBCO/MgO) thin films have been investigated by microstrip resonator technique. The penetration depth λ0(0 K ) and the microwave surface resistance Rs can be obtained by analyzing the experimental data of the temperature dependence of resonant frequency, unload quality factor of the microstrip resonator. The stress in the two thin films can be obtained from their XRD patterns. The result shows that the stronger stress in YBCO/LAO thing film makes it have larger microwave surface resistance at lower temperature.

Properties of TBCCO 2212 Thin Films for Electronic Applications

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1321-1326 ◽  
Author(s):  
A. Andreone ◽  
A. Cassinese ◽  
F. Palomba ◽  
G. Pica ◽  
M. Salluzzo ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Resistance ◽  
Electrical Characterization ◽  
Chemical Vapor ◽  
Ex Situ ◽  
Inductive Method ◽  
Organic Chemical ◽  
Microstrip Resonator ◽  
X Ray ◽  
Two Samples

We report on the synthesis and structural and electrical characterization of high quality Tl 2 Ba 2 Ca 1 Cu 2 O x superconducting thin films. The samples have been prepared ex-situ by a combined approach of Metal-Organic Chemical Vapor Deposition (MOCVD) and thallium vapor diffusion. The films have been grown on 10×10 mm 2 (100) LaAlO 3 substrates. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analyses (EDX) have investigated the morphological and compositional nature of the films. The transport properties have been measured using both a four-probes and an inductive method. The highest critical temperature and critical current density are 104 K and 1 × 106A/cm2 respectively. The microwave response of two samples has been studied using a microstrip resonator technique. The best surface resistance values are below 200 μΩ at 1.2 GHz and 4.2 K. Measurements of the field dependence of the surface resistance have been performed.

THE MICROWAVE PROPERTIES OF THE DOUBLE-SIDED THIN FILM MgB2 RESONATOR

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3493-3496
Author(s):  
YUNFEI WANG ◽  
LIBIN SHI ◽  
LIPING CHEN ◽  
SHENG LUO ◽  
GUOHUA ZHANG ◽  
...  
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Magnesium Diboride ◽  
Chemical Vapor ◽  
Microstrip Resonator ◽  
Sapphire Substrates ◽  
Microwave Characteristic ◽  
Physical Chemical ◽  
Different Temperatures ◽  
Zero Resistance

Double-sided magnesium diboride ( MgB 2) thin films have been grown on double-sided polished sapphire substrates by the technique of hybrid physical chemical vapor deposition (HPCVD). The zero resistance temperature ( Tc ) of the films is higher than 37 K. The microwave characteristic of the double-sided MgB 2 thin films at 8.7GHz is studied systematically by the microstrip resonator technique. Surface resistance of the thin films is extracted by analyzing the resonance curves at different temperatures, and it is 1.2 mΩ at 11K.

Effects of Residual Surface Resistance on the Microwave Properties of YBCO Thin Films

2005 ◽  
Vol 15 (2) ◽  
pp. 3706-3709 ◽  
Author(s):  
A. Porch ◽  
D.W. Huish ◽  
A.V. Velichko ◽  
M.J. Lancaster ◽  
J.S. Abell ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Resistance ◽  
Microwave Properties ◽  
Ybco Thin Films

Temperature depeddence of the microwave surface resistance of YBCO thin films from microstrip resonator measurements

1991 ◽  
Vol 175 (5-6) ◽  
pp. 603-606 ◽  
Author(s):  
I.S. Gergis ◽  
P.H. Kobrin ◽  
J.T. Cheung ◽  
E.A. Sovero ◽  
C.L. Lastufka ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Resistance ◽  
Microwave Surface Resistance ◽  
Microstrip Resonator ◽  
Ybco Thin Films

Highly Oriented Very Low Surface Resistance Tl2Ba2Cu2O8 Films on NdGaO3 and LaAlO3

1992 ◽  
Vol 275 ◽  
Author(s):  
William L. Holstein ◽  
Louis A. Parisi
Keyword(s):  
Thin Films ◽  
Surface Resistance ◽  
Microwave Properties ◽  
Full Width ◽  
Half Maximum ◽  
Rocking Curve ◽  
Substrate Film

ABSTRACTLow surface resistance epitaxial Tl2CaCu2O8 thin films were prepared on orthorhombic (001) NdGaO3 and pseudocubic (100) LaAlO3. The films were c-axis oriented on both substrates, with [100] Yl2Ba2CaCu2O8 parallel to [110] NdGaO3 or pseudocubic [100] LaAlO3. The orientation was particularly good on NdGaO3, where the rocking curve full width at half maximum was 0.19°. Films on LaAlO3 exhibit high Tc and exceptional microwave properties: inductive superconducting Tc of 106 ± 2 K, onset of flux exclusion at 107.6 ± 0.5 K, and 10 GHz surface resistance of 130 ± 20 μΩ at 77 K. These results represent the highest reported Tc of any Tl2Ba2CaCu2O8 films and the lowest surface resistance at 77 K of any films of any phase on any substrate reported to date. On NdGaO3, in spite of a substrate-film reaction, films with high Tc and good microwave properties were also produced: inductive Tc of 105 ± 2 K, onset of flux exclusion at 104.0 ± 0.5 K, and 10 GHz surface resistance at 77 K of 600 ± 100 μΩ.

Defects in β-SiC thin films grown on α-SiC substrates

1988 ◽  
Vol 46 ◽  
pp. 568-569
Author(s):  
Karren L. More
Keyword(s):  
Thin Films ◽  
Semiconductor Device ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Growth Interface ◽  
Si Substrates ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.

Microstructural characterization of YBa2Cu3O7-x thin films formed by metalorganic CVD

1991 ◽  
Vol 49 ◽  
pp. 1080-1081
Author(s):  
P. Lu ◽  
W. Huang ◽  
C.S. Chern ◽  
Y.Q. Li ◽  
J. Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Growth ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Ion Milling ◽  
Conventional Grinding

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.

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