Effect of Thermal Oxidation on the Structural and Magnetic Properties of TbFe2 Alloys

Because of its highest magnetostriction at room temperature, TbFe<inf>2</inf> is one of the most promising materials for magnetostrictive applications. However, oxidation-induced deterioration in its magnetic properties limits its usage at higher temperature (T) and/or longer time (t). In this regard, a systematic study is performed here to understand the effect of oxide-film overgrowth (by varying T and t) on the microstructure and magnetic properties of TbFe<inf>2</inf>. The characteristic parameters of magnetic properties, such as coercivity (H<inf>c</inf>) and remanent magnetization (M<inf>r</inf>), are found to decrease with increasing T and/or t. Moreover, a strong correlation between the oxidation-induced microstructure and magnetic properties is observed. Understanding developed in this study will help in choosing optimum working conditions (i.e., T and/or t) for TbFe<inf>2</inf> to avoid significant deterioration in the magnetic properties.