We have performed Raman scattering measurements on bismuth ferrite (BiFeO3) nanoparticles and studied both magnetic and lattice modes. We reveal strong anomalies between 140 K and 200 K at the frequency of magnon and E(LO1), E(TO1), and A1(LO1) phonon modes. These anomalies are related to a surface expansion and are enhanced for nanoparticle sizes approaching the spin cycloidal length. These observations point out the strong interplay between the surface, the lattice, and the magnetism for sizes of BiFeO3 nanoparticles close to cycloid periodicity.

Topics
Ferroelectric materials, Lattice dynamics, Magnons, Multiferroics, Phonons, Raman spectroscopy, Thermal effects, Nanoparticle
© 2020 Author(s).
2020
Author(s)
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