Molecular Beam Epitaxy Growth of Superconducting Ba1-xKxFe2As2 and SmFeAs(O,F) Films
Abstract
We report the molecular beam epitaxy (MBE) growth of the iron-based superconductors, Ba1-xKxFe2As2 and SmFeAs(O,F). In the growth of Ba1-xKxFe2As2 films, the key to incorporating volatile K in films is low-temperature (≤350 °C) growth in reduced As flux. The highest Tc thus far obtained is Tcon (Tcend) = 38.0 K (35.8 K). In the growth of superconducting SmFeAs(O,F), we adopted two methods. In the first method, we first grew pristine SmFeAsO films, and subsequently introduced F into the films by diffusion from an overlayer of SmF3. In the second method, we grew as-grown superconducting SmFeAs(O,F) films by coevaporating Sm, SmF3, Fe, and As. Thus far, better results have been obtained by the first F diffusion method. The films prepared by F diffusion showed Tcon (Tcend) = 56.5 K (55.3 K), whereas the as-grown films showed Tcon (Tcend) = 51.5 K (48.0 K).
- Publication:
-
Japanese Journal of Applied Physics
- Pub Date:
- January 2012
- DOI:
- 10.1143/JJAP.51.010103
- Bibcode:
- 2012JaJAP..51a0103U