Ferromagnetic Effects in Cr-Doped Fe<sub>2</sub>O<sub>3</sub> Thin Films

Abstract

Among various phases of iron oxide, hematite (Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) has attracted world attraction owing to its stability, oxidation, and corrosion resistance. Undoped and Cr-doped Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 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 Cr <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> as compared with iron cation. M-H curves of Cr-doped Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 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.