Large magnetoelectric effect and low-loss high relative permittivity in 0–3 CuO/PVDF composite films exhibiting unusual ferromagnetism at room temperature

Abstract

Flexible magnetoelectric 0–3 composite films formed with high dielectric (ε r ∼ 104) CuO microparticles in a polyvinylidene fluoride (PVDF) polymer matrix showed multifunctional properties. The films prepared by the hot-moulding technique exhibit low-loss high relative permittivity (ε eff ∼ 103) with good ferroelectric behaviour (with P–E loop) at the percolation threshold (f CuO = f c ∼ 0.25). Dielectric, ferroelectric, magnetic and direct magnetoelectric properties of the composites depend strongly on the CuO filler concentration (f CuO). Interesting low field magnetoelectric response appears with about 5% decrease in ferroelectric polarization in the insulating composite (f CuO = 0.20) along with 7.5% increase in the magnetodielectric coefficient under a magnetic field of 6 kG in the semiconducting percolative composite at room temperature. At this field, a maximum magnetoelectric voltage coefficient of 1.45 mV cm−1 Oe−1 was obtained. Even though the CuO sample is paramagnetic at ambient temperature, this typical composite film exhibits weakly ferromagnetic (with M–H loop) behaviour indicating multiferroic character. Our result represents an important step towards practical device applications using the high dielectric and magnetoelectric effects.

Temperature and frequency dependence of the dielectric and piezoelectric response of P(VDF–TrFE)/CoFe2O4 magnetoelectric composites

“…However, these laminated and ceramic composites have some limitations such as low resistivity and high dielectric losses which make them not so viable for device miniaturization and fabrication [4,8,9]. Furthermore, to simplify the preparation process as well as to avoid the problem of inter-diffusion between the piezoelectric and magnetostrictive phases, it is also important to select materials, which require significantly lower processing temperatures [9].…”

“…However, these laminated and ceramic composites have some limitations such as low resistivity and high dielectric losses which make them not so viable for device miniaturization and fabrication [4,8,9]. Furthermore, to simplify the preparation process as well as to avoid the problem of inter-diffusion between the piezoelectric and magnetostrictive phases, it is also important to select materials, which require significantly lower processing temperatures [9]. In this context, polymer based ME nanocomposites which can overcome the flaws of the abovementioned structures are an interesting, challenging and innovative research field and most probably will bridge the gap between fundamental research and applications in the near future [8,10].…”

Analysis of Smart Piezo-Magneto-Thermo-Elastic Composite and Reinforced Plates: Part II – Applications

“…Typical examples include resonators, phase shifters, delay lines and filters, magnetic field sensors, energy harvesting transducers, miniature antennas, data storage devices and spintronics, biomedical sensors for EEG/MEG devices and other relevant equipment, see [5][6][7][8][9][10][11][12][13][14].…”

Magnetoelectric coupling in Fe 3 O 4 /P(VDF-TrFE) nanocomposites

“…Thus, the ME coupling is described as an extrinsic product property since neither phase (piezoelectric nor magnetic/magnetostrictive) is magnetoelectric. Intrinsic linear ME effect has been observed in single-phase materials (intrinsic ME effect) such as antiferromagnetic Cr2O3 crystal or multiferroic BiFeO3 compound but the associated ME susceptibilities are low compared to those of laminate composites [22][23][24][25][26][27].Among the piezoelectric compounds some specific functional polymers such as Poly(vinylidine Fluoride) (PVDF) polymer and its copolymer Poly(vinylidene fluride/trifluoroethylene) P(VDF-TrFE) have been widely studied and used as organic matrix in magnetoelectric structures for their interesting ferroelectric properties [7,9,10,11,[20][21][22][23][24][25][26][28][29][30][31][32][33][34]. Although the higher ME coefficients have been reported for ceramic composites [35], an advantage of using P(VDF-TrFE) -Fe3O4 composites is the more simple elaboration process in a various range of shapes and the absence of brittleness.…”

“…Among the piezoelectric compounds some specific functional polymers such as Poly(vinylidine Fluoride) (PVDF) polymer and its copolymer Poly(vinylidene fluride/trifluoroethylene) P(VDF-TrFE) have been widely studied and used as organic matrix in magnetoelectric structures for their interesting ferroelectric properties [7,9,10,11,[20][21][22][23][24][25][26][28][29][30][31][32][33][34]. Although the higher ME coefficients have been reported for ceramic composites [35], an advantage of using P(VDF-TrFE) -Fe3O4 composites is the more simple elaboration process in a various range of shapes and the absence of brittleness.…”