Infrared reflectance spectra of an epitaxial Bi2FeCrO6 thin film prepared by pulsed laser deposition on LaAlO3 substrate were recorded between 10 and 900 K. No evidence for a phase transition to the paraelectric phase was observed, but some phonon anomalies were revealed near 600 K. Most of the polar modes exhibit only a gradual softening, which results in a continuous increase of the static permittivity on heating. It indicates that the ferroelectric phase transition should occur somewhere above 900 K. Magnetic measurements performed up to 1000 K, revealed a possible magnetic phase transition between 600 and 800 K, but the exact critical temperature cannot be determined due to a strong diamagnetic signal from the substrate. Nevertheless, our experimental data show that the B-site ordered Bi2FeCrO6 is one of the rare high-temperature multiferroics.
@article{arxiv.0712.3645,
title = {Infrared and magnetic characterization of the multiferroic Bi2FeCrO6 thin films in a broad temperature range},
author = {S. Kamba and D. Nuzhnyy and R. Nechache and K. Zaveta and D. Niznansky and E. Santava and C. Harnagea and A. Pignolet},
journal= {arXiv preprint arXiv:0712.3645},
year = {2009}
}