Raman scattering study on relaxor ferroelectric Pb(In1/2Nb1/2)-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals

Abstract

The vibrational property of relaxor ferroelectric Pb(In1/2Nb1/2)-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals was investigated by using Raman scattering. The angular dependences of two Raman bands, one located at ∼50 cm−1 and the other at ∼560 cm−1, were investigated in the paraelectric phase where no Raman bands are allowed in the average \(Pm\bar 3m\) symmetry. The angular variation of the Raman intensity of the strong low-frequency mode at ∼50 cm−1 was compatible with the F2g mode of \(Fm\bar 3m\) symmetry, indicating that this mode could be attributed to the 1:1 chemical order at the B-site in PIN-PMN-PT. The high-frequency Raman mode at ∼560 cm−1 exhibited an intensity modulation consistent with the rhombohedral R3m symmetry, suggesting that this mode was related to polar nanoregions. The intensity ratio of the depolarized to the polarized component of this high-frequency mode showed an abrupt change when PIN-PMN-PT underwent a structural phase transition into the rhombohedral phase.