Manganese-doped feroxyhyte nano-urchins produced by chemical methods

Mn-doped feroxyhyte (δ-FeOOH) nanoparticles were synthesized using a wet chemical method, starting from a mixture of iron and manganese salts. The particles obtained were needle-like, around 100 nm in length, and formed had a nano-urchin structure. The compositions of the four samples obtained were calculated to be δ-Fe0.92Mn0.08OOH, δ-Fe0.75Mn0.25OOH, δ-Fe0.56Mn0.44OOH, and δ-Fe0.32Mn0.68OOH. The superparamagnetic behavior of the nanoparticles was determined from their room-temperature Mossbauer spectra. The hyperfine magnetic field of the Mn-doped δ-FeOOH nanoparticles decreased when iron atoms were substituted by Mn atoms. Furthermore, Mn atoms were locally doped into δ-FeOOH.