Zero-field 57Fe NMR in BiFeO3 based compounds: Problems, solutions and application to Bi1-xSrxFeO3

In this paper, we present a protocol designed to avoid typical problems occurring in the process of the spatial spin modulated structure (SSMS) investigation in BFO-based (BiFeO3) materials by zero-field nuclear magnetic resonance (ZF NMR) spectroscopy on 57Fe nuclei. We have analyzed the significant discrepancies in the parameters of the spectra in the literature and developed the measurement protocol to improve the quality and unify the obtained spectra. The study of the 57Fe spectra of Sr-doped BFO at 4.2 K samples was carried out to illustrate the protocol. The obtained spectra demonstrate suppression of the SSMS by heterovalent substitution. The Sr-concentration dependent evolution of the SSMS anharmonicity parameter was observed as well. •There is a discrepancy in BFO-based materials anharmonicity parameter determination.•The developed protocol provides the higher quality and uniformity of the spectra.•The SSMS structure persists in Sr-doped BFO up to 14% Sr concentration.•57Fe and 209Bi contributions can be separated by appropriate design of the experiment.