Multiferroic CoFe₂O₄–Ba_0.95Ca_0.05Ti_0.89Sn_0.11O₃ Core–Shell Nanofibers for Magnetic Field Sensor Applications

Multiferroic materials with coexisting of at least two ferroic orders (ferromagnetic, ferroelectric, or ferroelastic) have recently attracted the interest of researchers due to their potential applications as multifunctional devices. Herein, we report the synthesis and detailed characterization of the multiferroic CoFe 2 O 4 –Ba 0.95 Ca 0.05 Ti 0.89 Sn 0.11 O 3 core–shell nanofibers (CFO@BCTSn NFs) prepared by a sol–gel coaxial electrospinning technique. The scanning and transmission electron microscopes were used to check nanofibers’ core–shell structure/configuration, with fiber diameters ranging from 150 to 250 nm. The X-ray diffraction analysis confirms the presence of both the spinel structure of the CFO and the perovskite structure of the BCTSn. Piezoresponse force microscopy and magnetic hysteresis were used to confirm the multiferroicity of CFO@BCTSn NFs. Notably, the maximum magnetization and remanent magnetization of NFs are found to be 11.63 emu g –1 and 1.43 emu g –1, respectively. Meanwhile, the maximum piezoelectric response d 33 eff is around 6 pm V –1 . The magnetoelectric (ME) coefficient obtained for the CFO@BCTSn NFs is 346 mV cm –1 Oe –1 at the field of 10 kG. These findings may lead to development of nanoscale Pb-free magnetic field sensors and magnetoelectric device applications.