Investigation of Un-reacted, Multi-phase, Solution-Derived Targets for Pulse Laser Deposition (PLD) of High T$_{c}$ Superconducting Y$_{2}$Ba$_{4}$Cu$_{8}$O$_{16}$ (Y248) In-Situ, Epitaxial Thin Films

Y$_{2}$Ba$_{4}$Cu$_{8}$O$_{16}$ (Y248) is known to be robust in terms of O stability and is characterized by the absence of twin formation, and no structural phase transitions. It is stable in ambient atmosphere, resisting H$_{2}$O (and possibly even CO$_{2}$ exposure). These characteristics make Y248 more attractive for several applications of thin film superconductors as compared to Y$_{1}$Ba$_{2}$Cu$_{3}$O$_{7-\delta }$ (Y123). In addition, Y248 is very likely to have a much lower 1/f electrical noise level than Y123. (Electrical noise in Y123 has been shown to arise from mobile O defects). This would be an important advantage, since it has been established that electrical noise is a performance limiting parameter for Y123 devices. Limited past work on Y248 films has shown that a traditional approach to the growth of thin films by PLD that use stoichiometric, fully reacted, single phase targets has not been successful in achieving in-situ, epitaxial Y248 films. Such studies have also indicated the potential for achieving in-situ, epitaxial, PLD Y248 films using an un-reacted, multi-phase, solution-derived target. We will present results of our work towards obtaining high quality, in-situ, epitaxial thin films of Y248 via PLD employing non-traditional targets.