209Bi NMR spectrum of BiFeO3 in the presence of spatial modulation of hyperfine fields

Abstract

A complicated spin-echo spectrum was observed for 209 Bi nuclei in a ferroelectric antiferromagnet BiFeO 3 in zero external field. This spectrum is the first example of nuclear quadrupole resonance of a system of diamagnetic atoms in a hyperfine magnetic field produced by the spatially modulated Fe 3+ spin system and varying in orientation and magnitude. An attempt is undertaken to theoretically simulate the spectrum.