Effect of nano-size on magnetostriction of BiFeO₃ and exceptional magnetoelectric coupling properties of BiFeO₃-P(VDF-TrFE) polymer composite films for magnetic field sensor application

The existence of magnetostriction in bulk BiFeO₃ is still a matter of investigation and it is also an issue to investigate the magnetostriction effect in nano BiFeO₃. Present work demonstrates the existence of magnetostrictive strain in superparamagnetic (SPM) BiFeO₃ nanoparticles at room temperature and the magnetoelectric (ME) coupling properties in composite form with P(VDF-TrFE). Despite few reports on the magnetostriction effect in bulk BiFeO₃ evidenced by the indirect method, the direct method (strain gauge) was employed in this work to examine the magnetostriction of SPM BiFeO₃. In addition, a high ME coupling coefficient was observed by the lock-in technique for optimized BiFeO₃_P(VDF-TrFE) nanocomposite film. These nanocomposite films also exhibit room-temperature multiferroic properties. These results provide aspects of material with immense potential for practical applications in spintronics and magneto-electronics applications. We report a ME sensor using SPM BiFeO₃_P(VDF-TrFE) nanocomposite film for detection of ac magnetic field.