Study of phase transitions and magnetoelectric coupling of laser ablated BiFeO(3) thin films by Raman scattering

: Palai R, Huhtinen H, Valdes RM, Pagan R, Katiyar RS

: 2007

: Proceedings : IEEE International Symposium on Applications of Ferroelectrics

: 2007 SIXTEENTH IEEE INTERNATIONAL SYMPOSIUM ON THE APPLICATIONS OF FERROELECTRICS, VOLS 1 AND 2

: IEEE INT FERRO

: 413

: 414

: 2

: 978-1-4244-1333-1

: 1099-4734

DOI: https://doi.org/10.1109/ISAF.2007.4393282(external)

Multiferroic epitaxial thin films of BiFeO(3) were grown on (100) SrTiO(3) substrates by pulsed laser deposition (PLD). The X-ray diffraction analysis shows that the films are highly c-axis oriented with high degree of crystallinity. The polarized Raman scattering shows the monoclinic structure of thin films at room temperature in contrary to the rhombohedral structure in the bulk and tetragonal and rhombohedral structure in the c-axis oriented thin films as reported earlier. The temperature variation (up to 1000 degrees C) of Raman scattering reveals spin-phonon coupling around 370 degrees C, the magnetic Neel temperature (T(N)). The disappearance of stronger Raman modes revealed the structural (ferroelectric to paraelectric) phase transition at around 820 degrees C temperature (T(c)). The observation of no softening of phonon modes indicates nonoconventional ferroelectric. We observed an intermediate phase between 820-950 degrees C before the transition to a high-temperature cubic phase.