Crystalline growth rate and microstructure in YBaCuO thin films (original) (raw)
Related papers
Journal of Crystal Growth, 1996
The surface morphology and the interface structure of superconducting YBaCuO thin films grown on SrTiO3 substrates by pulsed electron beam evaporation have been studied using scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The crystal structure and epitaxial orientation of the films have been analysed using X-ray diffraction. Parametric studies of the effect on the structural development of
Applied Surface Science, 1998
Ž. Ž. Ž. YBCO superconducting films were deposited by XeCl s 308 nm pulsed laser deposition PLD on 100-oriented SrTiO , MgO and Si single crystal substrates. Control of the YBCO thin film epitaxial growth and microstructure quality are 3 important factors for superconducting electronic device applications. In this aim, we studied the influence of the oxygen pressure during the growth, the distance between target-substrate and substrate structure on the degree of structural Ž. Ž. orientation and surface quality of the films. X-ray diffraction XRD , scanning electron microscopy SEM and atomic force Ž. microscopy AFM techniques were used to make comparative studies of microstructure with transport properties of the films. q 1998 Elsevier Science B.V.
Early stages of growth of YBa2Cu3O7−δ high Tc superconducting films on (001) Y-ZrO2 substrates
Journal of Applied Physics, 1994
The early stages of growth of high quality YBa2Cu307--6 (YBCO) films grown on (001) Y-ZrOa (YSZ) substrates by pulsed laser deposition have been studied using a combination of atomic force microscopy and transmission electron microscopy. A one unit cell thick YBCO layer and relatively large CuO particles formed in the initial stages. Additional YBCO grew on top of the first laier in the form of one or a few unit cell high c-axis oriented islands about 30 nm in diameter. The rounded islands subsequently coalesced into faceted domains. Elongated Y,BaCuO, particles nucleated after the first layer of YBCO. A highly textured BaZrO, layer formed between the YSZ and the YBCO with a cube-on-cube dominant orientation relationship with respect to the YBCO film.
Growth mechanism and properties of YBa2Cu3O7 thin films deposited by laser ablation on (001) SrTiO3
Revista Romana de materiale = Romanian journal of materials = RRM
High quality, single phase c-axis oriented YBa2Cu3O7-δ thin films with superconducting properties were grown by laser ablation on (001) SrTiO3 substrates. The surface morphology of the films has been investigated by means of high-pressure reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), and scanning electron microscopy (SEM), while the structural properties were studied by X-ray diffraction (XRD). Deposition under optimum conditions produces films with relatively smooth surface, with a roughness of about 10-15 nm, as confirmed by AFM and SEM data. The growth follows a Stransky-Krastanov mechanism governed by the substrate-film interface properties due to presence of epitaxial strain. The films show good superconducting properties with Tc values of 85-91 K. Preliminary data on transport properties of YBa2Cu3O7-δ based ramp-type Josephson junction with a PrBa2Cu3O7-δ barrier are presented in the last part of the paper.
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.
Study of Excimer Laser Irradiation Effects on Properties of Crystalline YBaCuO Thin Films
Acta Physica Polonica A
The influence of UV laser irradiation on the physical properties of epitaxial YBa 2 Cu 3 O 7−δ thin (< 1 µm) films fabricated by laser ablation was studied. The samples were irradiated by pulsed excimer laser beam at different incident energy densities Eir ≤ 130 mJ/cm 2 , i.e. 2-3 times below the ablation threshold of YBaCuO. The analysis of the sample cross-section using transmission electron microscope shows that such irradiation forms a disordered layer on the top of the crystalline film. Sample surface amorphization was observed also by atomic force microscope. Due to strong UV irradiation absorption in YBaCuO this surface layer acts like a protective cover for the sample interior. Only a small reduction of superconducting critical temperature T c was observed. Both transport measurements in normal state and magneto-optical studies in superconducting state indicate that between the disordered layer and the bottom non-modified part of the film there exists a wide transitional region with reduced carrier concentration.
In situ preparation of superconducting YBaCuO thin films on bare silicon
Vacuum, 1990
Large scale applications of high Tc superconducting thin films in microelectronics depend strongly on the successful preparation of high quafity material using conventional substrates like Si or GaAs. By means of the pulsed laser deposition technique, thin Y-Ba-Cu-O films on bare single crystal silicon substrates are deposited. To overcome problems due to strong substrate-film interdiffusion and thus the formation of a highly disordered lattice, the deposition of crystalline material is mandatory. This is accomplished in our experiments using substrate temperatures as high as 700... 820°C during deposition. Our films grow as single phase material with the c-axis perpendicular to the film plane. No post deposition treatment is required to obtain high critical temperatures. Our best films so far show metallic behaviour and zero resistance temperature Too "-~ 8OK. A parameter study of in situ grown thin films shows that the optimum for the deposition temperature depends on the oxygen partial pressure. Our best films grow at Ts = 780°C and p = 1 mbar as well as at Ts = 720°C and p = 0.5mbar.
Growth and properties of YBa2Cu3O7−x superconducting thin films
Thin Solid Films, 1988
YBa2CuaOT-x films have been grown by reactive magnetron sputtering in an Ar + 02 sputtering atmosphere. As-grown films were amorphous and insulating and require a post-deposition annealing to show superconducting transitions on cooling. The best zero-resistance temperature T O was measured to be 85 K with a transition width of 5 K. Josephson supercurrent tunneling was also observed in these films and was linked to the accumulation of the impurities at the grain boundaries. Cation stoichiometry was found to be dependent on the deposition conditions, especially the presputtering of the target prior to the deposition. Target surface analysis showed that a relatively thick layer has to be removed from the surface of the target before the true bulk composition can be achieved in the films.
Effect of Nb2O5 and V2O5 addition on the superconducting properties of YBa2Cu3O(y) thin films
1995
The effect of Nb2O5 and V2O5 addition on the superconducting properties and microstructure of YBa2Cu3O(y) has been studied in thin films. Polycrystalline targets for laser ablation were prepared by mixing high purity V2O5 or Nb2O5 powders with a well characterized YBa2Cu3O(y) powder in the range 0 to 4 wt percent by solid state reaction method. Thin films (approximately 1500 A thickness) of the above targets were grown on (100) SrTiO3 (STO) and (100) LaAlO3 (LAO) substrates at 700 C temperature by pulsed laser deposition (PLD) technique. In the case of Nb2O5 addition we have noticed an increase in J(sub c) up to 0.5 wt percent and higher additive concentration (greater than 0.5 wt percent) have degraded the superconducting properties. However, in the case of V2O3 addition, there is an improvement in current density and microstructural properties up to 1 wt percent and the superconducting properties degrade for concentrations greater than 1 wt percent. The best J(sub c) for 0.5 wt pe...