Ferromagnetic Effects in Cr-Doped Fe2O3 Thin Films

Among various phases of iron oxide, hematite (Fe₂O₃) has attracted world attraction owing to its stability, oxidation, and corrosion resistance. Undoped and Cr-doped Fe₂O₃ thin films were prepared using sol-gel spin coating method. XRD results indicate that incorporation of chromium causes contraction in the unit cell, which, according to Bragg´s law, leads to shift of peak positions to higher diffraction angles. Contraction in unit cell is because of the smaller ionic radius of Cr³⁺ as compared with iron cation. M-H curves of Cr-doped Fe₂O₃ thin films show transition from weak ferromagnetic to strong ferromagnetic behavior as a function of dopant concentration. The change in magnetic properties has been correlated to the change in energies and structures of hematite with incorporation of chromium.