Synthesis andin situion irradiation of A-site deficient zirconate perovskite ceramics

The influence of A-site vacancies on zirconate perovskite structured ceramics of formula A(1-x)La(2x/3)ZrO(3)(A = Ca, Sr, Ba) has been investigated using 400 keV Kr(+)in situion irradiation in a TEM with varied temperature from 100 K to 673 K. The solubility limit of La within the Ba(1-x)La(2x/3)ZrO(3)system was 5.33 ml% (x= 0.08) using a solid-state synthesis route, with space group symmetry ofPm3m for x <= 0.08. The Ca(0.9)La(0.067)ZrO(3)and Sr(0.9)La(0.067)ZrO(3)samples were found to synthesise single-phase with thePcmnandPbnmsymmetries of their respective end member structures. The addition of 6.67 ml% La (x= 0.1) in CaZrO(3)and SrZrO(3)was found to decrease the critical temperature of amorphisation,T-c, in comparison with the undoped structures. A similar decrease was found for the 5.33 ml% La doped BaZrO(3)structure. Namely, values were observed for doped samples of approximate to 404 K, approximate to 520 K and approximate to 621 K (A = Sr, Ca, Ba respectively), compared to approximate to 440 K, approximate to 623 K and approximate to 675 K for SrZrO3, CaZrO(3)and BaZrO3, respectively. This follows similar behaviour to that observed in titanate systems at low dopant levels, and these findings have been discussed in relation to both the presence of cation vacancies in the doped samples and the presence of the La cation. Void formation, growth and induced morphology changes have also been characterised, onset by ion irradiation.