Wide range (20–200 nm) size control of spherical ferrite particles grown on seed crystals in aqueous solution added with sucrose

Spherical particles of ferrite (intermediate between Fe₃O₄ and γ-Fe₂O₃) were grown on seed crystals (∼9 nm) via the green rust route in an aqueous solution added with sucrose, which promotes spherical growth. By highly dispersing the seed crystals in an HNO₃ solution, we could control the diameter of the particles over a wide range of 20–200 nm (geometric standard deviation: 1.1–1.4) by changing the amount of the seed crystals. At the beginning of the seed growth, clusters of the seed crystals were resolved into smaller clusters, each composed of a few seed crystals.