Supplemental Material for the manuscript:
Strain-driven broken twin boundary coherence in YBa2Cu3O7-δ nanocomposite
thin films
R. Guzman1, J. Gazquez1,2,a), V. Rouco1, A. Palau1, C. Magen3, M. Varela2,4, J.
Arbiol1,5, X. Obradors1, T. Puig1
1
Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la
UAB, 08193 Bellaterra, Catalonia, Spain,
2
Materials Science & Technology Division, Oak Ridge National Laboratory,
Oak Ridge, Tennessee 37831, USA
3
Laboratorio de Microscopías Avanzadas, Instituto de Nanociencia de Aragon-
ARAID and Departamento de Física de la Materia Condensada, Universidad de
Zaragoza, 50018 Zaragoza, Spain
4
Departamento de Física Aplicada III, Universidad Complutense de Madrid,
28040 Madrid, Spain
5
Institucio Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona,
Catalonia, Spain
a)
Author to whom correspondence should be addressed. Electronic address:
jgazqueza@gmail.com
1
As discussed in the main manuscript this supporting information document provides
further information on the microstructure of standard and nanocomposite solution
derived YBa2Cu3O7-δ (YBCO) thin films.
Figure S1 shows a global picture of the microstructure of both an standard YBCO and
an YBCO nanocomposite thin films. These Z-contrast Scanning Transmission Electron
Microscopy (STEM) images were acquired with a FEI Titan (60-300 kV) equipped with
a probe-aberration corrector, Figure S1(a) is a low magnification Z-contrast image of a
standard YBCO specimen. The Y248 planar defects discussed in the manuscript are
common structural defects in YBCO thin films. In a Z-contrast image 248 planar
defects appear as horizontal black stripes, as observed on the right part of the image.
Although there are defect-free areas in standard films, Y248 planar defects can be
extended until the micrometer range, as observed in Figure S1(a). Figure S1(b), a higher
Z-contrast image, shows a close up region of the substrate interface, where two isolated
248 defects are found within the YBCO matrix. Conversely, YBa2Cu3O7-δ-BaZrO3
(YBCO-BZO) nanocomposites present a completely different microstructure. The
introduction of randomly oriented BZO nanoparticles into the YBCO matrix
dramatically increases the density of planar defects. Figure S1(c) shows a low
magnification Z-contrast image of an YBCO-BZO thin film, where homogeneously
distributed nanoparticles, seen as bright spots in the Z-contrast image, are observed. The
large interface mismatch between the nanoparticles and the matrix produces noncoherent interfaces what generates a huge increase in the nucleation of Y248 defects [1].
Figure S1(d), a higher magnification Z-contrast image, shows a much higher density of
Y248 defects, as compared to the non-doped, standard film (Figure S1(b)).
Figure S2(a) shows cross-sectional image from a standard YBCO thin film acquired
with a conventional transmission electron microscopy (TEM), a JEOL TEM 2100F
microscope operated at 200KV, in bright field mode and under two beam condition,
when the diffraction vector is g = (200). The observed contrast variation is due to the
alternation of the [100] and [010] axes across the twin boundaries (TB). As observed, in
a defect-free region the TBs are coherent, not being broken or truncated. Figure S2(b)
shows a plan-view bright field image of a standard, un-doped, YBCO thin film with
(100) as the diffraction vector, g = (100). In YBCO twin domains are shaped in the form
2
of lamellae parallel to their {110} twin boundaries. As observed, there are extended
defect-free regions.
Figure Captions
FIG S1. (a) Low magnification Z-contrast image of a standard YBCO film. (b) Higher
magnification Z-contrast image of YBCO showing the interface between the film and
the substrate. (c) Low magnification Z-contrast image of an YBCO-BZO
nanocomposite film. Brighter spots correspond to BZO nanoparticles. (b) Higher
magnification Z-contrast image of an YBCO-BZO nanocomposite showing the interface
between the film and the substrate. Y248 intergrowths appear as dark stripes in high
resolution Z-contrast images.
FIG S2. (a) Low magnification bright field TEM image of a cross-section YBCO thin
film under two beam condition, when the diffraction vector is g=(200). (b) Low
magnification plan-view bright field TEM image under two beam condition when the
diffraction vector is g=(100).
References
1.
A. Llordés, A. Palau, J. Gázquez, M. Coll, R. Vlad, A. Pomar, J. Arbiol, R.
Guzmán, S. Ye, V. Rouco, F. Sandiumenge, S. Ricart, T. Puig, M. Varela, D.
Chateigner, J. Vanacken, J. Gutiérrez, V. Moshchalkov, G. Deutscher, C. Magen
and X. Obradors, Nature Materials 11, 329–336 (2012).
3