Epitaxial lift-off of strontium titanate thin films and the temperature dependence of the low frequency dielectric properties of the films

1997 ◽  
Vol 493 ◽  
Author(s):  
M. J. Dalberth ◽  
J. C. Price ◽  
C. T. Rogers
Keyword(s):  
Strontium Titanate ◽  
Low Frequency ◽  
Dielectric Constants ◽  
Thermally Activated ◽  
Lanthanum Aluminate ◽  
Barium Copper ◽  
Dielectric Constant And Loss ◽  
Acid Etch ◽  
Yttrium Barium ◽  
Lift Off

ABSTRACTUsing pulsed laser ablation, we have grown epitaxial bilayers of strontium titanate (STO) and yttrium barium copper oxide (YBCO) on lanthanum aluminate (LAO) and neodymium gallate (NGO) substrates. Using a selective acid etch, we have removed the YBCO from the middle of the bilayer and lifted off the strontium titanate films from their parent substrates. Using coplanar interdigital capacitors patterned on the films' surface, we have measured the dielectric constant and loss as a function of frequency and temperature and have resolved frequency dependent loss peaks which indicate thermally activated behavior. Also, by applying a dc bias to the capacitor, we have seen tuning of the lifted off films' dielectric constants that compares favorably to films attached to substrates.

Dielectric Response of free Standing Strontium Titanate Thin Films from 10 Khz to 1 Ghz as A Function of Temperature and Applied Voltage

1999 ◽  
Vol 574 ◽  
Author(s):  
M. J. Dalberth ◽  
J. C. Price ◽  
C. T. Rogers
Keyword(s):  
Strontium Titanate ◽  
Dielectric Response ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Barium Copper Oxide ◽  
Free Standing ◽  
Thermally Activated ◽  
Barium Copper ◽  
Acid Etch ◽  
Yttrium Barium

AbstractUsing pulsed laser ablation, we have grown epitaxial bilayers of strontium titanate (STO) and yttrium barium copper oxide (YBCO) on (110) neodymium gallate (NGO) substrates. Using a selective acid etch, we have removed the YBCO from the middle of the bilayer and lifted off the STO films from their parent substrates. Using coplanar interdigital capacitors patterned on the surface of the films, we have measured the capacitance and loss as a function of frequency (from 10 kHz to 1 GHz), temperature (from 300 K to 4 K), and applied electric field (up to roughly 2 V/μm). We have seen frequency dependent loss peaks in the films that indicate thermally activated behavior, and an improvement in the tuning quality.

scholarly journals Quantitative Analysis of Yttrium Barium Copper Oxide Films on Strontium Titanate

2002 ◽  
Vol 8 (S02) ◽  
pp. 1484-1485
Author(s):  
Eric Lifshin ◽  
Michael S. Hatzistergos ◽  
Jodi L. Reeves ◽  
Raynald Gauvin
Keyword(s):  
Quantitative Analysis ◽  
Yttrium Barium Copper Oxide ◽  
Copper Oxide ◽  
Strontium Titanate ◽  
Oxide Films ◽  
Barium Copper Oxide ◽  
Barium Copper ◽  
Yttrium Barium

Pulsed Microwave Processing of High-TC Superconducting Films

1992 ◽  
Vol 269 ◽  
Author(s):  
R. B. James ◽  
R. A. Alvarez ◽  
A. K. Stamper ◽  
X. J. Bao ◽  
T. E. Schlesinger ◽  
...  
Keyword(s):  
Phase Transition ◽  
Barium Copper Oxide ◽  
Precursor Film ◽  
Silicon Substrates ◽  
Molten Layer ◽  
Time Resolved ◽  
Barium Copper ◽  
In Situ Experiments ◽  
Yttrium Barium

ABSTRACTWe have used 2.0-μsec microwave pulses at a frequency of 2.856 GHz to rapidly heat thin amorphous yttrium-barium-copper-oxide (YBCO) films deposited onto silicon substrates. The samples were irradiated inside a WR-284 waveguide by single-pass TE10 pulses in a traveling wave geometry. X-ray diffractometry studies show that an amorphous-to-crystalline phase transition occurs for incident pulse powers exceeding about 6 MW, in which case the amorphous YBCO layer is converted to Y2BaCuO5. Microscopy of the irradiated film reveals that the phase transition is brought about by melting of the YBCO precursor film and crystallization of the molten layer upon solidification. Time-resolved in situ experiments of the microwave reflectivity (R) and transmissivity (T) show that there is an abrupt change in R for microwave pulse powers exceeding the melt threshold, so that measurements of R and T can be used to monitor the onset of surface melting.

Superconducting Yttrium Barium Copper Oxide Thin Films Growing on the Strained Substrates

2008 ◽  
Vol 3 (4) ◽  
pp. 25-32
Author(s):  
Aleksandr V. Zakharov ◽  
Aleksandr B. Muravjev ◽  
Irina S. Pozygun ◽  
Gennadiy M. Seropyan ◽  
Sergey A. Sychev ◽  
...  
Keyword(s):  
Thin Films ◽  
Current Density ◽  
Superconducting Devices ◽  
Single Crystal Substrate ◽  
Superconducting Thin Film ◽  
Elastic Stresses ◽  
Barium Copper ◽  
Crystal Substrate ◽  
Long Time ◽  
Yttrium Barium

The article is devoted to formation of superconducting thin films on the single-crystal substrate where areas with different values of the critical current density are, that is needed for fabrication of superconducting devices. The method is based on an establishment of elastic mechanical stresses on the substrate crystal under the nanosecond focused pulsed laser irradiation. On the irradiated substrate the superconducting thin film having auxiliary elastic stresses not till the area is over the irradiated section of the substrate is grown. At the same time the critical film current density is suppressed for required values are used to fabricate Josephson junctions. Observations for a long time demonstrate superconducting transport film properties are not varied significantly during the maintenance.

scholarly journals Flux Penetration Effects in High-Tc SQUIDs

1989 ◽  
Vol 42 (4) ◽  
pp. 401
Author(s):  
GJ SIoggett ◽  
lK Harvey ◽  
L Wieczorek ◽  
RE Binks ◽  
R Driver
Keyword(s):  
Magnetic Field ◽  
Copper Oxide ◽  
Direct Measurement ◽  
Barium Copper Oxide ◽  
Break Junction ◽  
Flux Penetration ◽  
High Tc ◽  
Bulk Ybco ◽  
Barium Copper ◽  
Yttrium Barium

Two experiments pertaining to the effects of intergranular flux penetration in high-Tc yttrium-barium-copper oxide (YBCO) SQUIDs are described. The first is a direct measurement of the flux noise of bulk YBCO exposed to the earth's magnetic field, and the second involves the fabrication and testing of break junction d.c. SQUIDs. Implications of a number of undesirable effects seen in these experiments are discussed.

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