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The present work report synthesis of four-layer Aurivillius compound with systematic replacement of A-site Bi 3 + cation via La 3 + . Four-layer Aurivillius structure and phase purity is confirmed by x-ray diffraction measurements. Raman spectroscopy measurement indicate that La replaces Bi from perovskite like slab. M o ¨ ssbauer spectroscopy measurement shows the presence of paramagnetic behaviour at room temperature and confirms the presence of Fe 3 + in octahedral environment. Further, magnetization measurements indicate paramagnetic nature down to 5K similar to parent compound (Bi 5 FeTi 3 O 15 ) and suggest La substitution at A-site does not induce the magnetic ordering. [ABSTRACT FROM AUTHOR]

We have investigated magnetic, structural and dielectric properties of Bi 5 FeTi 3 O 15 (BFTO) in the temperature range 5K-300 K. Using diffraction, Raman spectroscopy and x-ray absorption fine structure measurements, iso-structural modifications are observed at low temperatures (≈100 K). The analysis of dielectric constant data revealed signatures of dielectric relaxation, concomitant with these structural modifications in BFTO at the same temperatures. Further, employing complementary experimental methods, it is shown that the distribution of Fe/Ti ions in BFTO is random. With the help of techniques that probe magnetism at various length and time scales, it is shown that the phase-pure BFTO is non-magnetic down to the lowest temperatures., (© 2021 IOP Publishing Ltd.)