Thin film deposition: a novel synthetic route to new materials

In this paper, we discuss the utility of thin film deposition as a syntheti c approach to the realization of new oxide materials. Thin film deposition has been shown previously to be well suited to stabilizing both highly meta stable phases and superlattices having unique atomic order which are not at tainable via classical preparatory routes. That this approach is only in th e early stages of realizing its full potential as a synthetic method is dem onstrated using classical pulsed laser deposition to grow new, artificially layered materials. Superlattices of metastable copper and manganese oxides having perovskite-like sub-cells were grown; they have the nominal formula e (La0.8Ba0.2CuO2.6+/-x)(m)(SrCuO2+delta)(n) and (LaMnO3)(m)(A'MnO3)(n) (A' = Sr and Y). Superlattice reflections are observed in the X-ray diffractio n spectra, indicative of a two-dimensional cationic order not observed in b ulk materials of similar stoichiometries. Moreover, the chemistry of the di mensionally confined layers in the superlattices differs from that of simil ar 'bulk-like' materials. Anomalous CMR effects are presented for the (LaMn O3)(m)(SrMnO3)(n) superlattices, demonstrating that new and unique; physica l properties are attainable via this particular synthetic approach. We also discuss the structure and growth mode of single films of LaMnO3 with respe ct to superlattice formation.