Microstructure and Magnetic Properties of LaMnO3 Coatings via Electrophoretic Deposition

This study investigates the microstructural and magnetic properties of LaMnO3 coatings fabricated by electrophoretic deposition (EPD) on stainless steel substrates. LaMnO3 powders were synthesized using a sol-gel citrate-nitrate auto-combustion method. The LaMnO3 suspension was diluted to 30 mg/50 ml using a mixture of ethanol and deionized water. The concentration of deionized water was adjusted to 10 mass% under an applied voltage of 60 V for 15 min. Surface morphology analysis revealed that the coating at 60 V exhibited a uniform, higher-density structure with a surface roughness of 30.96 nm. X-ray diffraction confirmed a rhombohedral structure with an R-3c space group and revealed slight lattice expansions correlated with increasing annealing temperature. Fourier-transform infrared (FT-IR) spectroscopy revealed characteristic peaks at approximately 580 cm⁻¹. This peak corresponds to an absorption band with a stretching mode associated with changes in the Mn–O–Mn bond length, which was an MnO6 octahedron according to the vibration characteristics of ABO3 perovskites. The magnetic properties, characterized using vibrating sample magnetometry (VSM), demonstrated that annealing at 950 °C yielded the highest saturation magnetization (Ms = 2.377 emu/g), indicating enhanced ferromagnetic behavior due to increased Mn3+/Mn4+ interactions.