Nanostructured magnetoceramics from hyperbranched polymer precursors

Controlled pyrolysis of a hyperbranched polysilyne, poly[1,1′-ferrocenylene(methyl)silyne] (1), at high temperature in inert atmosphere produces nonostructured ceramics (2) in ∼48–62% yields. The ceramic products 2 are characterized by SEM, XPS, EDX, XRD, and SQUID. It is found that the ceramics are electrically conductive and possess a mesoporous architecture. The iron contents of 2 estimated by EDX are 36–43%. The nanocrystals formed in the ceramics produced under nitrogen 2N are mainly α-Fe2O3 whereas those in the ceramics produced under argon 2A are mainly Fe3Si. When magnetized by an external field at room temperature, 2A exhibits a high saturation magnetization (Ms∼49 emu/g) and near-zero remanence and coercivity.