The growth mechanism and topography of superconducting YBa2Cu3O7−δ and BiSrCaCuO-2201 films studied by scanning tunneling microscopy

“…Figure 2 shows the XRD pattern of sample C10, deposited with the parameters reported in table 1, and, as demonstrated by the R-T measurements described in the following, exhibiting the best electrical properties. We utilized the experimental results available in the literature, [14,15,16], to identify the YBCO diffraction peaks. All the YBCO reflections can be indexed as (00l), with l = 1-7, demonstrating a complete c-axis orientation of the film.…”

Section: Ybco Thin-filmsmentioning

confidence: 99%

Pulsed laser ablation deposition and characterization of superconductive/ferroelectric bilayers

Ceresara

Iembo

Fuso

et al. 1996

Supercond. Sci. Technol.

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Superconductive/ferroelectric YBCO/PZT bilayer structures have been deposited by pulsed laser ablation on (100) MgO and SrTiO 3 substrates. Before the fabrication of the bilayer, optimization of the YBCO deposition parameters was carried out to improve the electrical, morphological and structural characteristics of the films. The results of x-ray diffraction spectroscopy, resistance versus temperature measurements, atomic force and scanning electron microscopies demonstrate the growth of YBCO films suitable as bottom layers for subsequent PZT deposition. The superconductive/ferroelectric bilayers, as characterized by x-ray diffraction and scanning electron microscopy, demonstrate the presence of the correct lattice structures for both YBCO and PZT layers and a good surface morphology (i.e. the absence of cracks and holes and low droplet density). The ferroelectric capacitors realized by using the YBCO layer and evaporated gold dots as bottom and top electrodes, respectively, exhibit excellent ferroelectric behaviour (remanent polarization P r ≈ 21 µC cm −2 , coercive field E c ≈ 100 kV cm −1 ), suggesting that laser deposited YBCO/PZT bilayers are promising as candidates for the fabrication of non-volatile random access memory devices.

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“…We define t r as the film thickness for which the total relaxation of the grown layer with the respect to the substrate structure is reached. 6,7 From the experimental point of view, it is not easy to determine the critical thickness t c by x-ray diffraction techniques since only a substantial relaxation degree can be revealed. Therefore, x-ray techniques may yield not very reliable results about the onset and formation of the first misfit dislocations.…”

Section: Introductionmentioning

confidence: 99%

“…The (00l)YBCO reflections with lϭ3,6,9,12 are not visible because they are in the same position as the most intense substrate peaks ͑STO͒.…”

mentioning

confidence: 96%

Microstructural and morphological analysis of ultrathin YBa2Cu3O7−x films grown by modulated magnetron sputtering on SrTiO3 substrates

Vecchio

Riccardis

Tapfer

et al. 2000

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The defect structure, the degree of crystalline perfection and the surface roughness of HTc superconductor films are affected by the initial layer configuration at the early stage of growth. In this work we report on structural and morphological investigations of ultrathin YBa2Cu3O7−x films grown on SrTiO3 substrate. The films are fabricated by inverted cylindrical magnetron sputtering with a modified deposition process based on the modulation of sputtering power. The modulated sputtering deposition promotes a higher in-plane grain connectivity and allows us to fabricate films with a lower defect density. The structural analyses of very thin films (thickness <25 nm) are performed by using low-angle x-ray specular reflectivity, double crystal diffraction, reciprocal space mapping and atomic force microscopy. The results indicate that a total relaxation of our films occurs at layer thickness larger than 25 nm. For thinner layers a tetragonal distortion of the unit cell and no twinning are observed. The low-angle measurements show distinct Kiessig fringes revealing a smooth surface and film/substrate interface. The off-specular reflectivity measurements indicate that the surface and interface roughness across the YBa2Cu3O7−x layer are uncorrelated.

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The growth mechanism and topography of superconducting YBa2Cu3O7−δ and BiSrCaCuO-2201 films studied by scanning tunneling microscopy

Cited by 27 publications

References 7 publications

Optimum sputtering conditions on the in-situ growth of superconducting YBa2Cu3Oy films with an off-axis RF sputtering configuration

Optimum sputtering conditions on the in-situ growth of superconducting YBa2Cu3Oy films with an off-axis RF sputtering configuration

Pulsed laser ablation deposition and characterization of superconductive/ferroelectric bilayers

Microstructural and morphological analysis of ultrathin YBa2Cu3O7−x films grown by modulated magnetron sputtering on SrTiO3 substrates

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