Fe-57 NMR study of a spatially modulated magnetic structure in BiFeO3

The Fe-57 spin echo spectra were studied in local magnetic fields of a BiFeO3 ferroelectric antiferromagnet over the temperature range 77-304 K. The line shape analysis confirmed the presence of a spatially modulated, incommensurate cycloidal spin structure in BiFeO3 and allowed the actual spin distribution to be reproduced throughout the cycloid length. The distribution was found to be essentially anharmonic. The modulated structure is stable over the whole temperature range studied. The cycloid wave becomes more harmonic with temperature elevation. (C) 2000 MAIK Nauka / Interperiodica.