TY  - JOUR
AU  - Palisaitis, Justinas
AU  - Ivanova, Mariya
AU  - Meulenberg, Wilhelm A.
AU  - Guillon, Olivier
AU  - Mayer, Joachim
TI  - Phase homogeneity analysis of La$_{0.99}$Sr$_{0.01}$Nb$_{0.99}$Al$_{0.01}$O$_{4−δ}$ and La$_{0.99}$Ca$_{0.01}$Nb$_{0.99}$Ti$_{0.01}$O$_{4−δ}$ proton conductors by high-resolution STEM and EELSK
JO  - Journal of the European Ceramic Society
VL  - 35
IS  - 5
SN  - 0955-2219
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - FZJ-2015-05641
SP  - 1517 - 1525
PY  - 2015
AB  - The microstructural and compositional homogeneity of La0.99Ca0.01Nb0.99Ti0.01O4−δ and La0.99Sr0.01Nb0.99Al0.01O4−δ proton conductors was studied using the combination of atomic-resolution scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS) and STEM image simulations. The obtained results revealed that gently doped proton conductors were predominantly composed of grains with a monoclinic lanthanum niobate crystal structure. In addition to the host phase, dopant-rich phases were also observed and identified. The La0.99Sr0.01Nb0.99Al0.01O4−δ matrix accommodated dopant-rich grains retaining an LaAlO3 cubic crystal structure with a significant fraction of Sr incorporated into them. The secondary phases embedded in the La0.99Ca0.01Nb0.99Ti0.01O4−δ matrix possessed the pyrochlore La2Ti2O7 crystal structure with Ca partially substituting La. High spatial resolution EELS revealed preferential Ca sites within the pyrochlore La2Ti2O7 crystal lattice. The origin of the secondary phase formation and the role of these phases for the transport properties of co-doped lanthanum niobates are discussed here.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000348686200018
DO  - DOI:10.1016/j.jeurceramsoc.2014.11.010
UR  - https://juser.fz-juelich.de/record/255479
ER  -