Further ordering structural investigation of Ba((Co,Zn,Mg)1/3Nb2/3)O3 perovskites by Raman spectroscopy

Correlations among the Raman vibration modes, ordering structures and dielectric properties have been established through further ordering structural investigation of BC((Co0-6-x/2Zn0.4.x/2Mgx)(1/)Nb-3(2/3))O-3 ceramics by Raman spectroscopy. Meanwhile an in-depth understanding of Raman spectroscopy for 1:2 ordered Ba(B-1/3'B-2/3 '')O-3 perovskites has been gained. An approximate 1:1 ordered structure composed of alternate NEP -rich and Nb5+-dfficient layers is detected by transmission electron microscopy observation, confirming that the four main Raman peaks of 1:2 ordered structure arise from the nanoscale regions of 1:1 ordering in B-site sublattice. As x increases, Ba-related and Nb-related phonons show growing lifetime with the increase of ordering degree and Qf values. Simultaneously, oxygen vibration along c axis (E-g((4)) (O) mode) is favored, while the vibration in ab plane (E-g((3))) (O) mode) weakens since 1:2 ordering forms along the c-axis of ordered structure. The lifetime of the oxygen-octahedron stretch A(1)g((4)) (O) mode (similar to 788 cm(-1)) is supposed not only influenced by the ordering domain size, but also the micro-defects such as ordering domain boundaries.