Synthesis and investigation of polyvinylpyrrolidone-polymer content on magnetic and electromagnetic properties of electrospun BiFeO₃, SrFe₁₂O₁₉, α-Fe₂O₃ nanostructures

A one-pot electrospinning technique was employed to synthesize polyvinylpyrrolidone (PVP)-based nanofibers containing bismuth ferrite (BiFeO 3 ), strontium hexaferrite (SrFe 12 O 19 ), and hematite ( α -Fe 2 O 3 ). The influence of PVP polymer concentration on structural properties revealed the formation of pure phases in all samples, except for BiFeO 3 nanofibers, which contained an impurity Bi 2 Fe 4 O 9 phase. Field-emission scanning electron microscope images showed that higher PVP concentrations resulted in longer, thicker nanofiber chains for all samples. Vibrating sample magnetometer analysis indicated that SrFe 12 O 19 nanofibers exhibited strong ferrimagnetic properties with high saturation magnetization (60 emu g −1 ) and coercivity (5000 Oe), while the other samples displayed weaker magnetic properties. To address the fragility of nanofibers produced via the one-pot method, the highest PVP concentration nanofibers were incorporated into low and high concentrations of paraffin matrices. Electromagnetic testing showed that paraffin concentration significantly increased the real part of electrical permittivity for BiFeO 3 nanofibers (from ∼2 to ∼4.5) compared to other compositions (∼2 to ∼3). Impedance results revealed that BiFeO 3 nanofibers had the lowest resistance and likely higher reflectivity. Lastly, the real permittivity of nanofibers decreased with increasing frequency, aligning with Koop’s dielectric relaxation theory.