Exploring complex magnetic behavior induced by Mn in LaNiO₃ perovskite

This study focuses on the synthesis and physical properties of Mn doped LaNiO₃ perovskite, a potential candidate for magnetic refrigeration. Herein, we report the facile synthesis of Mn substituted LaNiO₃ using a sol–gel process and examine its complex magnetic properties. A Rietveld refinement revealed that the prepared sample has a rhombohedral unit cell with a R 3 ¯ c space group. A single-phase nature of prepared compound was further confirmed by Raman spectroscopy. Presence of mixed valance states of Mn and Ni ions was established by X-ray photoelectron spectroscopy, thereby resulting complex magnetic features in the compound. This results in the room temperature ferromagnetic state being exhibited due to the high spin state of Mn³⁺, whereas pristine LaNiO₃ compound exhibits paramagnetic state at room temperature. According to the Curie–Weiss law, the positive Curie–Weiss temperature (θ_CW= 262 K) indicated ferromagnetic (FM) ordering predominates over antiferromagnetic (AFM) interactions. As a result of this study, it is shown that a suitable dopant can tune the magnetic state through controlled defects in the structure, and that such features can be utilized in the fabrication of similar perovskites for future magnetic applications.