PEROVSKITE RELATED PHASES IN THE ND4TI4O14-NDTIO3 SYSTEM

Layered perovskite structures with the series formula A(n)B(n)O(3n+2) have been prepared in the Nd4Ti4O14 - NdTiO3 system. The phases were p roduced by argon arc melting and were investigated by powder X-ray dif fraction and high resolution electron microscopy. As the global compos ition moved from Nd4Ti4O14 (n=4) towards NdTiO3 the new phases Nd9Ti9O 31 (n=4.5) Nd5Ti5O17, (n=5) Nd11Ti11O37 (n=5.5), Nd6Ti6O20, (n=6) were produced. In addition disordered materials made up of intergrowths of perovskite-like slabs were identified. The phase Nd6Ti6O20 coexisted with a non-stoichiometric perovskite phase with approximate compositio n NdTiO3.15. This latter material possessed the GdFeO3 distorted perov skite-type structure. Electron microscopy revealed the presence of a m icrodomain texture in some samples, indicating a microstructure more c omplex than that of the parent phase.