X-ray diffraction line broadening effects in MBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}(M=Y, Gd) thin films
- Dipartimento di Ingegneria dei Materiali, Universita di Trento, I-38050 Mesiano (Tunisia) (Italy)
- CNR-ISM, Via Gobetti 101, I-40129 Bologna (Italy)
- HTS Laboratory, ICTP, P.O. Box 586, I-34100 Triesti (Italy)
- CNR-LAMEL, Via Gobetti 101, I-40129 Bologna (Italy)
X-ray diffraction line profile analysis (LPA) has been carried out on a set of superconducting thin films of MBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (MBCO, M=Y, Gd), deposited by pulsed and continuous physical vapor deposition (PVD) techniques on different single-crystal substrates. The choice of appropriate deposition conditions, substrates, and buffer layers promoted a high degree of [00{ital l}] preferred orientation, leading to a well-defined columnar grain morphology in the MBCO films. Under such conditions, the LPA of diffraction patterns, collected with the widely spread Bragg{endash}Brentano geometry, gives a detailed information on the distributions of coherent scattering domain (crystallite) size and microstrain along the [00{ital l}] growth direction; considering the particular MBCO film microstructure, the mean crystallite size ({bar M}) can be regarded as the mean distance between extended planar defects parallel to the film surface. The significance of {bar M} goes beyond a merely statistical value. As long as the morphology of the films is similar, {bar M} is found to be strictly connected with the average microstrain by a simple proportionality relation. Moreover, the correlation extends to important superconducting transport parameters, like the transition width {Delta}T{sub c}. These regular behaviors are irrespective of deposition techniques, substrate and film materials, and are a clear indication of some fundamental relation between the defects and the overall properties of the films. {copyright} {ital 1997 Materials Research Society.}
- OSTI ID:
- 450278
- Journal Information:
- Journal of Materials Research, Vol. 12, Issue 1; Other Information: PBD: Jan 1997
- Country of Publication:
- United States
- Language:
- English
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