Vibrational Studies of A(B’2/3B’’1/3)O3 Perovskites (A = Ba, Sr; B’ = Y, Sm, Dy, Gd, In; B’’ = Mo, W)
M. Maczka; J. Hanuza; A.F. Fuentes; Y. Morioka. Vibrational Studies of A(B’2/3B’’1/3)O3 Perovskites (A = Ba, Sr; B’ = Y, Sm, Dy, Gd, In; B’’ = Mo, W). Journal of Physics: Condensed Matter (ISSN: 0953-8984). 2004, Vol. 16, p. 2297-2004.
The Raman- and IR-active phononswere studied in ordered Ba(Y2/3Mo1/3)O3, Ba(Y2/3W1/3)O3, Ba(Gd2/3W1/3)O3, Ba(Sm2/3W1/3)O3, Ba(Dy2/3W1/3)O3, Ba(Dy2/3Mo1/3)O3 and Ba(In2/3W1/3)O3 as well as disordered Ba(In2/3Mo1/3) O3 and Sr(In2/3W1/3)O3. The assignment of the observed modes was given on the basis of lattice dynamical calculations. The studies performed revealed the presence of forbidden by the selection rules Raman bands for the Ba(In2/3Mo1/3)O3 sample. This result suggests that the Ba(In2/3Mo1/3)O3 contains 1:1 ordered domains of Fm-3m symmetry embedded in the disordered Pm-3m matrix and that Ba(In2/3Mo1/3)O3 and Ba(In2/3W1/3)O3 may be obtained in both ordered and disordered structures, depending on the thermal treatment. This behaviour resembles that of well known Pb(In1/2Nb1/2)O3, Pb(Sc1/2Nb1/2)O3 and Pb(Sc1/2Ta1/2)O3 relaxors
The Raman- and IR-active phononswere studied in ordered Ba(Y2/3Mo1/3)O3, Ba(Y2/3W1/3)O3, Ba(Gd2/3W1/3)O3, Ba(Sm2/3W1/3)O3, Ba(Dy2/3W1/3)O3, Ba(Dy2/3Mo1/3)O3 and Ba(In2/3W1/3)O3 as well as disordered Ba(In2/3Mo1/3) O3 and Sr(In2/3W1/3)O3. The assignment of the observed modes was given on the basis of lattice dynamical calculations. The studies performed revealed the presence of forbidden by the selection rules Raman bands for the Ba(In2/3Mo1/3)O3 sample. This result suggests that the Ba(In2/3Mo1/3)O3 contains 1:1 ordered domains of Fm-3m symmetry embedded in the disordered Pm-3m matrix and that Ba(In2/3Mo1/3)O3 and Ba(In2/3W1/3)O3 may be obtained in both ordered and disordered structures, depending on the thermal treatment. This behaviour resembles that of well known Pb(In1/2Nb1/2)O3, Pb(Sc1/2Nb1/2)O3 and Pb(Sc1/2Ta1/2)O3 relaxors