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arXiv · 0706.0404

Room temperature coexistence of large electric polarization and magnetic order in BiFeO3 single crystals

Delphine Lebeugle·Dorothee Colson·Anne Forget·Michel Viret·Pierre Bonville·Jean-Francis Marucco·Stephane Fusil
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Abstract

From an experimental point of view, room temperature ferroelectricity in BiFeO3 is raising many questions. Electric measurements made a long time ago on solid-solutions of BiFeO3 with Pb(Ti,Zr)O3 indicate that a spontaneous electric polarization exists in BiFeO3 below the Curie temperature TC=1143K. Yet in most reported works, the synthesised samples are too conductive at room temperature to get a clear polarization loop in the bulk without any effects of extrinsic physical or chemical parameters. Surprisingly, up to now there has been no report of a P(E) (polarization versus electric field) loop at room temperature on single crystals of BiFeO3. We describe here our procedure to synthesize ceramics and to grow good quality sizeable single crystals by a flux method. We demonstrate that BiFeO3 is indeed ferroelectric at room-temperature through evidence by Piezoresponse Force Microscopy and P(E) loops. The polarization is found to be large, around 60 microC/cm2, a value that has only been reached in thin films. Magnetic measurements using a SQUID magnetometer and Mossbauer spectroscopy are also presented. The latter confirms the results of NMR measurements concerning the anisotropy of the hyperfine field attributed to the magnetic cycloidal structure.

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Delphine Lebeugle, Dorothee Colson, Anne Forget, Michel Viret, Pierre Bonville, Jean-Francis Marucco, Stephane Fusil. 2007-06-04. Room temperature coexistence of large electric polarization and magnetic order in BiFeO3 single crystals. https://doi.org/10.1103/physrevb.76.024116

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