Temperature-Dependent Raman Scattering of Multiferroic Pb(Fe1/2Nb1/2)O3
Journal of Physics-Condensed Matter, Volume 23, Issue 1, 015401-1 - 015401-6. DOI: 10.1088/0953-8984/23/1/015401
Raman scattering measurements on multiferroic Pb(Fe1/2Nb1/2)O3 over a wide temperature range from 10 to 500 K were performed. Very broad and overlapping peaks (first-order character) and a prominent high-frequency peak at ~ 1130 cm − 1, which we assign as a two-phonon peak, were observed. These features showed remarkable changes in their Raman scattering intensity and spectral shape at the characteristic temperature T* ~ 330 K, clearly showing a structural lattice change at around T*. The temperature dependence of some stretching vibration modes of the BO6 units revealed an anomalous frequency shift below TN ~ 143 K. These anomalous deviations at TN of the phonon frequency are associated with the spin–phonon coupling mechanism. Complementary magnetic data confirmed a weak magnetic ordering at room temperature and interestingly showed an anomaly at about T*. These results suggest an interplay between ferroelectric, structural and magnetic degrees of freedom in PFN, starting to be significant at around T*.
A. F. García-Flores, Dmitri A. Tenne, Y. J. Choi, W. J. Ren, X. X. Xi, and S. W. Cheong. "Temperature-Dependent Raman Scattering of Multiferroic Pb(Fe1/2Nb1/2)O3" Journal of Physics: Condensed Matter 23.1 (2011): 015401.
Available at: http://works.bepress.com/dmitri_tenne/17