The effect of substrate-off-cut on the properties of epitaxial thin films of YBa2Cu3O7−δ grown by pulsed laser deposition (original) (raw)
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Surface and in-plane characterization of YBa2Cu3O7 thin films grown by laser ablation
Physica C: Superconductivity, 1991
We have used reflection high energy electron diffraction (RHEED) and oscillating crystal X-ray diffraction to analyze the surface and in-plane structural characteristics of YBa~Cu30, (YBCO) thin films that were grown in-situ by laser ablation onto substrates of (100) MgO and (100) SrTiO3. We obtain RHEED streaks, characteristic of atomically smooth surfaces and indicative of epitaxial order, for these thin films. Oscillating crystal diffraction also indicates that the YBCO film axes are collinear with the substrate axes. The films grown on (! 00) substrates are solely c-axis oriented (perpendicular to the plane of the film) as determined by 0-20 diffractometry and the FWHM of rocking curves about the (005) reflection are 0.3 ° to 0.5 ° for the best films on SrTiO3 substrates and 0.4: to 0.6: for films grown on MgO. Weissenberg photography allo~'s us to determine the in-plane structure of some films grown on MgO that display anomalous surface features seen by RHEED and by scanning electron microscopy.
OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS
Experimental results concerning the pulsed laser deposition parameters of in-situ epitaxially grown high crystalline quality YBa2Cu3O7-x thin films are reported. The structural and morphological properties of the deposited films analyzed by transmission electron microscopy, selected area electron diffraction, X-ray diffraction, and Raman spectroscopy are also presented. The YBa2Cu3O7-x thin films, predominantly c-axis oriented had required the smallest oxygen pressure during the cool-down time reported to date.
Physica C-superconductivity and Its Applications, 1994
Epitaxial films of (110) or ( 103 ) YBa2CuaO7_x grown on (110) SrTiO3 substrates by laser abla,.;on are compared to (001 ) films. Their microstructure is investigated with scanning tunneling microscopy, scanning electron microscopy and high-resolution transmission electron microscopy. The growth of steps, terraces and spirals originating from screw dislocations commonly seen in c-axis films is inhibited in films grown on (110) SrTiO3. In the case of (103) oriented films, the growth of 90 ° twisted domains produces a tooth-like structure with preferred orientation. The influence of vicinal substrates (a few degrees of misorientation ) on the film growth, on the nature of defects and on the resistive behavior is also investigated.
Ceramics International, 2013
ABSTRACT a-Axis- and c-axis-oriented YBa2Cu3O7–δ (YBCO) films were grown on (100) SrTiO3 substrate by laser chemical vapour deposition (laser CVD). The effect of lattice mismatch between films and substrates on in-plane and out-of-plane crystallinity and critical temperature (TC) was investigated. The preferred orientation changed from a-axis to c-axis as the deposition temperature increased from 928 to 1049 K. The c-axis-oriented YBCO showed a minimum of full width at half maximum of 0.5° for the ω-scan and 1.0° for the φ-scan. A smaller mismatch between YBCO films and substrates led a higher crystallinity for in-plane and out-of-plane epitaxial growths. A high TC of 90 K was obtained for the c-axis-oriented YBCO films. The deposition rate of the YBCO films was 58–101 μm h−1, approximately 60–1000 times higher than that of conventional CVD.
Monocrystalline YBa[sub 2]Cu[sub 3]O[sub 7−x] thin films on vicinal SrTiO[sub 3] (001) substrates
Applied Physics Letters, 2003
The correlation between the vicinal properties of SrTiO 3 ͑001͒ substrates and the twinning in YBa 2 Cu 3 O 7Ϫx thin films grown by pulsed-laser deposition is studied using x-ray diffraction with reciprocal space mapping. The vicinal properties, i.e., angle and in-plane orientation, play a significant role in the anisotropic strain starting at the interface between substrate surface and film, and affect the twin behavior of YBa 2 Cu 3 O 7Ϫx . On substrates having an ͓110͔ in-plane orientation of the step edges, a completely preferred twin pair is observed if the vicinal angle is increased to 0.60°. Whereas on substrates having their step edges oriented along one of the crystallographic axis, the films exhibit a detwinning as the vicinal angle increases. For ␣ϭ1.10°a maximum detwinned, i.e., monocrystalline film is obtained. At this angle, the diffusion length of YBa 2 Cu 3 O 7Ϫx during the growth matches the terrace length of SrTiO 3 . Up to this specific angle, the films are grown perpendicular to the optical instead of the crystallographic surface.
YBa2Cu3O7-δ Thin Film Growth on Different Substrates by Pulsed Laser Deposition
2017
There were a lot of research on YBa 2 Cu 3 O 7-δ (YBCO) superconducting materials and this material still draw attention. In this research, thin films of commonly used superconducting YBCO ceramic material, grown on LaAlO 3 (LAO), MgO and SrTiO 3 (STO) substrates as thin films, which have different thermal expansion constants and lattice parameters, by Pulsed Laser Deposition (PLD) technique. For all growths, 150 mTorr partial Oxygen pressure, 5 cm substrate-target distance and 800 °C substrate temperature were used. Thin films were characterized for film quality and microstructure with X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) techniques. Analysis of these thin films showed that mainly c oriented (00l) YBCO thin films obtained with LAO and STO substrates which are more compatible than MgO substrates for YBCO growth.
Epitaxial growth of YBa2Cu3O7−δ thin films on LiNbO3 substrates
Applied Physics Letters, 1989
I n situ epitaxial growth of YBa2Cu3O7−δ thin films on Y-cut LiNbO3 substrates using a standard laser ablation technique is reported. Resistance of the films shows a normal metallic behavior and a very sharp (<1 K) superconducting transition with Tc(R=0) of 92 K. High critical current density of Jc(77 K)=2×105 A/cm2 is observed, which is in accordance with epitaxial growth. Film orientation observed from x-ray diffraction spectra indicates that the c axis is normal to the substrate plane and the a axis is at 45° to the [11.0] direction of the hexagonal lattice of the substrate with two domains in mirror image to the (110) plane.
Ceramics International, 2015
YBa 2 Cu 3 O 7 À x film was prepared on (001) SrTiO 3 single crystal substrate by spray atomizing and coprecipitating laser chemical vapor deposition. At laser power of 101-116 W (corresponding deposition temperature was 893-942 K), a-axis-oriented YBa 2 Cu 3 O 7 À x film was prepared, which showed an epitaxial growth mode of YBa 2 Cu 3 O 7 À x [100]‖SrTiO 3 [001] (YBa 2 Cu 3 O 7 À x [001]‖SrTiO 3 [100]). The a-axisoriented YBa 2 Cu 3 O 7 À x film had critical temperature of 75-82 K, with critical current density from 0 to 0.4 MA cm À 2. At laser power of 167-181 W (corresponding deposition temperature was 1093-1154 K), c-axis-oriented YBa 2 Cu 3 O 7 À x film was obtained, whose epitaxial growth mode was YBa 2 Cu 3 O 7 À x [001]‖SrTiO 3 [001] (YBa 2 Cu 3 O 7 À x [100]‖SrTiO 3 [100]). A c-axis-oriented YBa 2 Cu 3 O 7 À x film prepared at a deposition rate of 14 μm h À 1 showed a high critical temperature of 91 K and critical current density of 2.8 MA cm À 2 .