Enhancement of $\beta $-phase in PVDF films embedded with ferromagnetic Gd$_{\mathrm{5}}$Si$_{\mathrm{4}}$ nanoparticles for piezoelectric energy harvesting

Self-polarized Gd5Si4-polyvinylidene fluoride (PVDF) nanocomposite films have been synthesized via a facile phase-inversion technique. For a 5 wt{\%} Gd5Si4-PVDF film, the enhancement of the piezoelectric $\beta $-phase from 49{\%} for pristine PVDF to 81{\%} for nanocomposite is confirmed using FTIR spectroscopy. The Gd5Si4 particles prepared using high-energy ball milling have a particle size of \textasciitilde 470 nm with a high magnetization of 11 emu/g. The analysis of the Gd5Si4-PVDF films revealed a change from diamagnetic behavior to enhanced ferromagnetism when pristine PVDF films are loaded with 2.5 wt{\%} and 5 wt{\%} Gd5Si4 nanoparticles. The increased $\beta $-phase fraction resulting from the addition of magnetic Gd5Si4 nanoparticles to membranes of PVDF paves the way for future efficient energy harvesting applications using a combination of magnetic and piezoelectric effects.