Polarization reversal in organic-inorganic ferroelectric composites: Modeling and experiment

Abstract

Tailoring of ferroelectric properties of copolymer P(VDF-TrFE) by incorporation of ceramic inclusions in the polymer matrix is promising for advanced applications in sensorics. We have observed experimentally that in composites of P(VDF-TrFE) with barium-doped lead zirconate titanate (BPZT), the remanent polarization increases, while the coercive field substantially decreases in comparison with the pure polymer samples. Results of simulation in framework of the modified Weiss model have shown that the changes of the hysteresis loops characteristics are due to increase of the dielectric susceptibility of the composite as compared to pure PVDF-TrFE. This originates from the strong dispersion of the mean field constant α, which describes the feedback of the polarization on the electric field at the location of the dipoles and is closely related with the local increase of composite susceptibility in the vicinity the BPZT inclusions. This phenomenon effectively becomes macro-scale due to the long-range nature of the inhomogeneous elastic and electric fields occurring at the interfaces between the matrix and inclusions.

Dielectric, Ferroelectric, and Piezoelectric Investigation of Polymer‐Based P(VDF‐TrFE) Composites

“…It is known that the effective dielectric constant in composite materials is dependent on the geometry of embedded fillers . The BPZT inclusions in our composites had a spherical shape with the average particle size ≈0.5 μm . It is clearly seen that the ratio of the effective permittivity of the composite to the matrix permittivity remains the same in a wide frequency range (Figure (b) and (c)).…”

“…The concentration of the filler varied from 10 to 50 vol.%. In our measurements, we used samples prepared by the same technique presented elsewhere . Films with thickness varying from 20 to 50 µm were obtained depending on the concentration of the filler.…”

“…Polymer‐based composites with embedded solid fillers can incorporate mechanical and electrical properties of its constituents. The ferroelectric polymer poly(vinylidene fluoride) (PVDF) and its copolymers with trifluoroethylene P(VDF‐TrFE) are perfect materials offering good mechanical compliance, relatively good dielectric and piezoelectric properties among other polymers . Incorporation of these properties is necessary in various devices starting from miniature capacitors for telecommunication high performance actuators or contact switches .…”

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

“…Usually, the addition of inclusions to the PVDF matrix is performed in order to lower the coercive field of the material. This was successfully performed with the inclusions of PZT based nanoparticles to PVDF-TrFE [27].…”

Influence of annealing conditions on elastic and dielectric properties of P(VDF‐TrFE) copolymer and its composites

“…The low‐temperature peak is, probably, related to the dynamic glass transition of the polymer matrix and the high temperature peak is related to the ferroelectric‐paraelectric phase transition of the crystalline region at T C2 . The ferroelectric‐paraelectric phase transition is of an order‐disorder type with the polarization as the order parameter .…”