Nanosize ferrites obtained by ball milling: Crystal structure, cation distribution, size-strain analysis and Raman investigations

Spinels samples Fe2.85Y0.15O4 (S1) and Fe2.55In0.45O4 (S2), such as Fe3O4 + gamma-Fe2O3 (S3) were obtained by ball milling. TEM micrograph as well as XRPD line broadening analyses show nanosize nature of the ferrite powders. Cation distribution, found by Rietveld refinement of the site occupancies, indicate Y3+ ions presence at 16d sites in Fe2.85Y0.15O4, and a random In3+ ions distribution on both 8a and 16d sites in Fe2.55In0.45O4 (space group Fd (3) over barm). From the XRPD line broadening analysis crystallite size and strain values were determined. The crystallite size and strain anisotropy is significant, especially for Fe2.85Y0.15O4 and Fe2.55In0.45O4. This result is discussed regarding the influence of the cation substitutions. The Raman signature confirms the spinel structure and the homogeneity of the particles. (c) 2006 Elsevier SAS. All rights reserved.