Deposition of La2Zr2O7 film by chemical solution deposition

Effect of oxygen partial pressure on the crystallization of CeO2 and La2Zr2O7 bi-axially textured thin films

“…As it was the first time, according to our knowledge that crystallization of oxide films was studied versus oxygen pressure, we have verified that the general trend observed for CeO 2 was also observed in La 2 Zr 2 O 7 films where residual carbon due to metal-organic precursor decomposition has important consequences [23,25,30]. After deposition, the films were heat treated at 950 1C in Ar-5% H 2 forming gas and submitted the same procedure as for CeO 2 .…”

“…Other pole figures showed no (2 2 0) orientated grains and comparison with the substrate shows an in-plane rotation of CeO 2 grains of 451 with respect to the crystal axis of the substrate, all of this confirms a pure epitaxial texture described by [1 0 0] CeO2 ///1 1 0S STO . However, the peak (2 0 0) has a relatively weak intensity at 850 1C and it is broad, what we suppose being related to the treatment under reducing atmosphere, a phenomenon also observed for La 2 Zr 2 O 7 in reducing conditions [25]. Increasing the temperature does not solve the problem since an interaction with STO is evidenced giving rise to amorphous product at 950 1C, crystallized SrCeO 3 and Ti 4 O 7 above this temperature; Ti 4 O 7 being a residue of the formation of SrCeO 3 .…”

“…Reducing atmosphere is also dictated for CC fabrication to avoid oxidation of the metallic substrate, especially for NiW alloys [23]. However, these conditions provide rather weak crystallinity as mentioned by several authors for CeO 2 deposited on YSZ [36,37] but also for LZO deposited on textured Ni-W alloy [25,38]. The weak crystallinity is then not a problem of the substrate, nor specific of a given type of oxide but more likely related to MOD in reducing conditions.…”

“…It results in a transparent and yellow solution, which is very stable when it is preserved from sun light and heat. Precursor for La 2 Zr 2 O 7 is prepared according to a procedure already described elsewhere [25,29] and composed of a clean solution of lanthanum and zirconium propionate (0.5 M) stable for months, this solution is called herein LaZr(prop) 7 .…”

“…CeO 2 and LZO are also used as buffer layers for 2 G YBCO coated conductors (CC) applications [23][24][25]. Metal-organic deposition (MOD) has been extensively used to form these oxide films on hyper-textured metals like Ni-W alloys used as tapes for CC [26].…”