## 3 Results and Discussion
Our results showed that with an increase in the crystallinity of an orthorhombic phase, a highly oriented film was formed compared with semi crystalline films with the \"pseudocubic phase\" reported before. Differences in FWHM values for the film and powder were 0.17264 and 0.18829, respectively, demonstrating the enhancement of the crystallinity for the film. The XRD pattern of as deposited BCY10 with an orthorhombic [23]_Pncm_ (PDF 01-083-5709) structure (Figure 3b) demonstrates a highly oriented crystallographic structure towards (002) and (213) (231). The high orientation is attributed to the orientation of the metal substrate [28], the e-beam formation conditions [36] that influence the crystallographic direction of the lowest surface energy and atomic composition [37], and it is associated with the increased number of grains along that plane, density and crystallinity [38], thickness, strain that can induce rotation, and the templated growth process [39]. Similar XRD patterns for BCY10 were observed in the thin film prepared by PLD at 750 \({}^{\circ}\)C [40]. Figure 3b also shows the XRD pattern of the BCY20 _Pm-3m_ phase (PDF 01-084-7856). An orthorhombic _Imma_[41] phase was reported when the samples were sintering in vacuum. Others report the formation of a rhombohedral phase [13] with a secondary Y\({}_{0.2}\)Ce\({}_{0.8}\)O\({}_{1.9}\) phase. An increase in the yttrium amount results  
Figure 2: SEM cross-sectional images of the thin films: BCO (**a**), BCY10 (**b**), BCY20 (**c**), BZO (**d**), BZY20 (**e**), and BZCY (**f**). in lower crystallite sizes being 24.2 nm and 10.3 nm for BCY10 and BCY20, respectively. FWHM values for BCO were lower (<0.4) compared to BCY10 and BCY20 (>0.5). The orientation direction changes with the percentage of concentration of the dopant due to a change in phase from orthorhombic to cubic. At a 10% yttrium concentration the predominant orientations are (024) (132), while only the (211) orientation remains predominant for the thin films with a 20% yttrium concentration. The preferential crystallographic orientations of the formed thin films are presented by the texture coefficients (Table 2). Figure 3: XRD patterns of (**a**) BCO thin films and initial powder; (**b**) BCY10 thin films and initial powders; and (**c**) BCY20 thin films and initial powder. However, the BZO thin films do not show a single barium zirconate structure, but consist of barium carbonate, BaO, and Ba\({}_{3}\)Zr\({}_{2}\)O\({}_{7}\), which partially overlaps with BaZrO\({}_{3}\) (Figure 4). Similarly, the BZY20 and BZCY thin films exhibit structures with additional oxides and carbonates. Such a mixture of phases can arise due to several reasons, one of them being the non-stoichiometry of the formed thin films and atomistic deposition by e-beam evaporation, in addition to the too low deposition temperature and a lack of further annealing. It is known that BaO reacts easily with the atmosphere towards the formation of BaCO\({}_{3}\)[27]. Therefore, a higher energy is needed to break the bond on the oxides. Additionally, oxygen vacancies enhance the diffusion [42]. At the end, a mixture of these two effects is involved in the diffusion process. These results suggest that an increase in temperature and power should be necessary to enhance the diffusion to obtain barium zirconates without additional phases. The crystallite size values were 12.0 nm and 8.6 nm for BZO and BZY20, respectively. It is known that a high power in an e-beam vapor deposition enhances the crystallinity and crystal size of the structures [43; 44]. Another parameter that results in the enhanced crystallinity is the thickness of the formed thin films. A thin film growth and crystallization occur by the formation of nucleation centers and their growth that are dependent on the thickness of the thin film. Crystal growth is then controlled by volume diffusion and the free energy change of a system that acts as its driving force [45].