Does the modulated magnetic structure of BiFeO3change at low temperatures?

High resolution neutron powder diffraction has been applied to verify the model of distorted cycloidal magnetic modulation proposed on the basis of NMR studies of the multiferroic BiFeO 3 in Zalesskii et al (2000 Europhys. Lett. 50 547). Our experimental results do not support the model of magnetic modulation given by Zalesskii et al for BiFeO 3 at 4 K. Neutron diffraction patterns recorded at ambient temperature and 4 K agree with the cycloidal magnetic modulation model for BiFeO 3 proposed by Sosnowska et al (1982 J. Phys. C: Solid State Phys. 15 4835). Present neutron diffraction results are compared with BiFeO 3 NMR and Mössbauer literature data.