This paper reviews the recent progress in the understanding of the dynamics of Pb(B_(1/2)B0_(1/2))O_(3)-type relaxor ferroelectrics using of broadband micro-Brillouin scattering spectroscopy,which covers a large frequ...This paper reviews the recent progress in the understanding of the dynamics of Pb(B_(1/2)B0_(1/2))O_(3)-type relaxor ferroelectrics using of broadband micro-Brillouin scattering spectroscopy,which covers a large frequency range from 1 to 1000 GHz by a tandem multi-pass FabryPerot interferometer.In contrast to Pb(B_(1/3)B0_(2/3))O_(3)-type relaxors,there is no frustration on the B-site of perovskite structure and the degree of order of B-site cations depends on heat treatment.Remarkable softening of sound velocity and an intense central peak are observed above the Curie temperature TC owing to the polarization°uctuations in polar nanoregions(PNRs).Unlike the Pb(B_(1/3)B0_(2/3))O_(3)relaxors,Pb(B_(1/2)B'_(1/2))O_(3)does not undergoes a typical diffuse phase transition without lead vacancies on A-site which enhances randomfields.For the(1-x)Pb(B_(1/2)B'_(1/2))O_(3-x)PbTiO_(3)solid solutions,the long range polar order increases as the PbTiO_(3)content increases.Nevertheless,a central peak owing to dynamic PNRs still remains even for the composition near the MPB,and a critical slowing down is clearly observed in the vicinity of TC.展开更多
文摘This paper reviews the recent progress in the understanding of the dynamics of Pb(B_(1/2)B0_(1/2))O_(3)-type relaxor ferroelectrics using of broadband micro-Brillouin scattering spectroscopy,which covers a large frequency range from 1 to 1000 GHz by a tandem multi-pass FabryPerot interferometer.In contrast to Pb(B_(1/3)B0_(2/3))O_(3)-type relaxors,there is no frustration on the B-site of perovskite structure and the degree of order of B-site cations depends on heat treatment.Remarkable softening of sound velocity and an intense central peak are observed above the Curie temperature TC owing to the polarization°uctuations in polar nanoregions(PNRs).Unlike the Pb(B_(1/3)B0_(2/3))O_(3)relaxors,Pb(B_(1/2)B'_(1/2))O_(3)does not undergoes a typical diffuse phase transition without lead vacancies on A-site which enhances randomfields.For the(1-x)Pb(B_(1/2)B'_(1/2))O_(3-x)PbTiO_(3)solid solutions,the long range polar order increases as the PbTiO_(3)content increases.Nevertheless,a central peak owing to dynamic PNRs still remains even for the composition near the MPB,and a critical slowing down is clearly observed in the vicinity of TC.
