Influence of Copper Doping on Structural, Magnetic, and Ferroelectric Properties of Bismuth Ferrite Nanofibers

This study explores the effects of Cu‐doping on the structural, magnetic, and ferroelectric properties of BiFeO 3 (BFO) nanofibers synthesized by the electrospinning technique. Rietveld refinement of the X‐ray diffraction patterns confirms the distorted rhombohedral‐hexagonal perovskite structure (R c space group) of the Cu‐doped BFO nanofibers. Field emission scanning electron microscope imaging reveals a decreased nanofiber diameter with Cu‐doping. High‐resolution transmission electron microscope reveals the highly crystalline nature of the as‐synthesized nanofibers. X‐ray photoelectron spectroscopy results indicate that the presence of the Fe 3+ oxidation state in the Cu‐doped fibers is favorable for magnetization. The BFO nanofibers’ magnetic properties improve with increasing copper (Cu) concentration, with a maximum at 3% Cu‐doping, which results in a magnetic saturation of 1.24 emu g −1 . The divergence between the zero‐field‐cooled and field‐cooled magnetization curves at low temperatures is indicative of spin‐glass behavior. Ferroelectric measurements show enhanced polarization with 3% Cu‐doping, giving saturation polarization of 0.059 μC cm −2 . These findings demonstrate that Cu‐doped BFO nanofibers are promising candidates for next‐generation multiferroic memory devices.