“…The most important points to take away from this work are (i) as the BFO particle size becomes smaller, the BiO 6 cage undergoes large distortions, and consequently, the FeO 6 octahedra rotate, (ii) the Bi–O bond lengths in nano BFO increase significantly (bond length distributions Bulk σ BiO1 2 = 0.0047 Å 2 and Nano σ BiO1 2 = 0.0052 Å 2 , Bulk σ BiO2 2 = 0.009 Å 2 and Nano σ BiO2 2 = 0.0128 Å 2 ) with a minor disorder in the FeO 6 cage (σ FeO = 0.04 Å), which also influences the interunit Fe–Fe disorder (Δσ FeFe 2 ≈ 44%), and (iii) the sublattice distortions of BiO 6 and FeO 6 result in a change in the Fe–O–Fe bond angle (due to common O), wherein the ideal Fe–O–Fe angle changes from 154.8 to <133°. Hence, the Bi–O disorder influences Fe–O – Fe, which in turn affects the DM superexchange interaction. , The milestone of this work, however, is its subtle focus on the topics, which are the prime focus to the multiferroic community: - By tuning the particle size of BFO, one may introduce topological ferromagnetism (FM shell–AFM core);
- Control of the particle size as an alternative to strain induced functional octahedral distortions for applications that require an amplified magnetoelectric effect; and
- Control of the particle size as an alternative to doping induced distortions. ,
…”