Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: SC: Fe-based Superconductors - 1111
TT 17.7: Vortrag
Montag, 14. März 2011, 19:45–20:00, HSZ 301
Epitaxial thin films of arsenic free pnictide supercondutors grown by molecular beam epitaxy — •Alexander Buckow, Jose Kurian, and Lambert Alff — Institute of Materials Science, TU Darmstadt
Within the family of superconducting pnictides, arsenic containing compounds not only are the largest in number, but also the materials with the highest critical temperatures, Tc, obtained so far (up to 55 K). However, from the viewpoint of applications As free superconductors are more desirable, and from the fundamental point of view, the role of other pnictogens is of interest.
For Bi as pnictogen, 1111 structure bulk superconductors have been found with Tc up to 9 K [1]. Here we report on the growth of arsenic free superconducting thin films by reactive
molecular beam epitaxy as a generic synthesis route. Besides the successful growth of superconducting thin films of LaONiBi, we have also grown the 122 phase LaNi2Bi2. These thin films were fabricated on MgO substrates from elemental sources in a custom designed UHV chamber (≈ 10−8 mbar). A streaky RHEED pattern during deposition clearly indicates epitaxial growth. The observed Laue oscillations in the X-ray diffraction patterns reveal the high crystallinity of the films. So far, however, we could not observe superconductivity in the Bi based 122 epitaxial thin films.
V. L. Kozhevnikov et al., JETP Lett. 87, 649 (2008).