Embedded polytypes in Bi2Sr2-xLaxCuO6 thin films grown by laser ablation

摘要: We investigate the presence of secondary phases in La-doped Bi-2201 thin films grown by laser ablation. The cation ratios target material, oxygen pressure, and substrate temperature during deposition are main parameters determining diluted intergrowth and/or polytype aggregates. A statistical model random is used to analyze x-ray diffraction (XRD) anomalies caused hidden defects characterize latter. detailed structural XRD refinement on oriented aggregates allows us identify guest phase as a Bi deficient phase, Bi-1201. occurrence this particular embedded accompanied global deficiency introduced growing process annealing treatment. La favors Bi-1201 formation mostly La-rich c-axis excess material improves considerably crystallographic structure Bi-2201, avoids formation, but does not prevent separation films. also influence type well their variation with doping. This work introduces specific methodology for optimizing growth ablation, which applies layered oxides that admit polytypes close enthalpies diagram.