Diagnosis of precipitate formation in pulsed-laser deposition ofYBa2Cu3O

Layer-by-layer growth of SrFeO3- thin films on atomically flat single-terminated SrRuO3/SrTiO3 (111) surfaces

“…Rather, they originated from transmission through small crystallites of a different stoichiometry from that of the SFO film. A lightscattering technique along with AFM revealed that Cu-rich precipitates were formed at the initial stages of YBa 2 Cu 3 O 7 À d (YBCO) growth on a TiO 2 -terminated STO (0 0 1) substrate [19]. The presence of the Cu-rich precipitates was confirmed also by 3D spots in the RHEED pattern [20].…”

Growth mechanism of YBa2Cu3O7–δthin films and precipitates on planar and vicinal SrTiO3substrates

“…Many publications proved the existence of island nuclei even for monolayer c-axis YBCO films, and the islands grew larger with the film thickness. 20,21 The chemical compositions of precipitates have been reported as Y-rich or Cu-rich phases, 6,7,10,22 while a similar composition as the YBCO film matrix has been frequently observed for island-shaped precipitates. Growth modes reported for c-axis YBCO films were the island growth mode, [13][14][15] spiral growth mode, [16][17][18] or layer-by-layer growth mode 19 above a certain film thickness, while the layer-by-layer growth mode did not occur for the initial growth stage of YBCO.…”

“…Islands nucleated even on the 7-Å-thick films for all YBCO films (region F). 10 The matrix surrounding precipitates was not the YBa 2 Cu 3 O 7−␦ , but the pseudomorphic phase in the early stage. 10,40,41,50 A pseudomorphic island growth was observed on ultrathin (<40 Å) YBCO films grown on STO and MgO substrates by sputtering deposition.…”

“…[10][11][12] It was indicated that the nucleation and growth mode for the island formation took place from the initial stage, and the island size depended on the film thickness. Many publications proved the existence of island nuclei even for monolayer c-axis YBCO films, and the islands grew larger with the film thickness.…”

High-quality off-stoichiometric YBa2Cu3O7−δ films produced by diffusion-assisted preferential laser ablation

“…13,15,17,26,33 If the diffusion of one of the cation species during film growth is the rate-limiting factor in forming YBa 2 Cu 3 O 6ϩx , a small excess amount of this element actually promotes the growth process, yielding better superconducting properties. It has been suggested 34 that Y is this diffusion rate-limiting element.…”