Magnetoelectric coupling in PVDF/Nano NaNbO₃/NanoNi composites: Influence of Ni particles aspect ratio

Abstract

In this work, three phase magnetoelectric nanocomposites are successfully prepared by solvent casting from α-PVDF. The extrinsic piezoelectric effect is insured by 20 vol% of NaNbO 3 ferroelectric nanoparticles prepared by the hydrothermal process. Nickel is chosen as the magnetic phase. In order to maintain insulation, electrical percolation is avoided by using nickel contents lower than the percolation threshold. Two different morphologies are employed: spherical nanoparticles (NiNPs) and nanochains (NNCs) with an aspect ratio of 80. NNCs are obtained by a polyol process under a magnetic field. Thin films of nanocomposites are processed by hot pressing. The real part of the dielectric permittivity (') of composites is governed by Maxwell-Wagner-Sillars polarization at the PVDF/Ni interfaces. An important increase of ' at low frequency is observed for PVDF/NaNbO 3 /NNCs composites; it favors the magnetoelectric coupling. Piezoelectric properties of composites are dependent upon mechanical modulus so that the most higher d 33 is obtained for PVDF / NaNbO 3 / NiNPs. Magnetoelectric coupling coefficient ( ME ) is determined from magnetoelectric intensity. PVDF / NaNbO 3 / NiNPs composites exhibit enhanced magnetoelectric coupling. The  ME coupling coefficient reaches 4.2V/(mOe). The magnetic properties are significantly improved by the NiNPs

Fabrication and magnetoelectric investigation of flexible PVDF-TrFE/cobalt ferrite nanocomposite films

“…Moreover, these materials offer unique advantages, such as they can be fabricated into different shapes, on molded structures and curved surfaces, thus, making them suitable for applications such as sensors, transducers, actuators, data storage, spintronics, and miniature antennas [5][6][7][8][9][10]. Magnetoelectric coupling in such polymers can be formed with the incorporation of ferromagnetic nanoparticles, and the coupling properties can be tuned by varying content and shape of nanoparticles in the composite systems [11,12].…”

“…Recently, many attempts have been made to produce magnetoelectric coupling between ferroelectric PVDF and ferromagnetic nanoparticles with good dispersion of nanoparticles [12,21]. However, little attention has been dedicated to developing the magneto-electric coupling in the copolymers.…”

“…A number of preparation methods have been reported for PVDF-based nanocomposites films using magnetic nanoparticles, such as PVDF-BiFeO 3 [26], PVDF-CoFe2O4 [27,28], PVDF-NaNbO 3 -Ni [12], PVDF-HFP/clay/NF [29], and PVDF-NiFe 2 O 4 [30,31], using either a solution casting, hot press, or electrospinning to improve the magneto-electric coupling. In those studies, enhancements in magneto-electric coupling and dielectric constant with the increase in filler nanoparticles were reported.…”

High aspect ratio galfenol flakes for high strain efficiency and sensing performance of magnetostrictive polymer composites

“…For many applications such as magnetic field sensing, high anisotropy is desirable to tailor the sensor signal-to-noise ratio and directionality. To date, shaping particles into high aspect ratios has been shown to improve the magnetostriction efficiency of magnetoelastic composites, 33 with some recent research exploiting this in nano-wire, 34 nano-ellipsoid, 35 and nano-chain 36 particles produced by using bottom-up processing routes. Further, chaining of low-aspect ratio particles has also been reported using magnetic fields during the manufacturing process.…”

Nickel‐Decorated Silver Nanowires for Polymer‐Based Magnetoelectric Composite

“…Some authors have also reported a magnetoelectric coupling with nickel particles in P(VDF-TrFE) [17] and in three-phased magnetoelectric composites. [18,19] In comparison with ferrites, nickel exhibits higher remnant magnetization at ambient temperature, which can be interesting to improve the magnetoelectric coupling in the composites. The main drawback of using metal instead of ceramics is the increase of the conductivity; it makes the poling of the matrix harder and then decreases the piezoelectric coefficient (d 33 ), especially for P(VDF-TrFE), which displays a high poling field 70 MV m À1 .…”