Magnetostrictive and Magnetoactive Effects in Piezoelectric Polymer Composites

A mesoscopic model for a polymer-based magnetoelectric (ME) composite film is developed. The film is assumed to consist of a piezoelectric polymer matrix of the PVDF type filled with CFO-like single-domain nanoparticles. The model is treated numerically and enables one to obtain in detail the intrinsic distributions of mechanical stress, polarization and electric potential and helps to understand the influence of the main configurational parameters, viz., the poling direction and the orientational order of the particle magnetic anisotropy axes on the electric response of the film. As the model is fairly simple-it uses the RVE-like (Representative Volume Element) approach with a single-particle cell-the results obtained are rather of qualitative than quantitative nature. However, the general conclusions seem to be independent of the particularities of the model. Namely, the presented results establish that the customary ME effect in composite films always comprises at least two contributions of different origins, viz., the magnetostrictive and the magnetoactive (magnetorotational) ones. The relative proportion between those contributions is quite movable depending on the striction coefficient of the particles and the stiffness of the polymer matrix. This points out the necessity to explicitly take into account the magnetoactive contribution when modeling the ME response of composite films and when interpreting the measurements on those objects.

Exploring bismuth-doped polycrystalline ceramic Ba0.75Bi0.25Ni0.7Mn0.3O3: synthesis, structure, and electrical properties for advanced electronic applications

This manuscript investigates the structural and electrical properties of a Ba0.75Bi0.25Ni0.7Mn0.3O3 (BNMO) perovskite compound synthesized through the sol-gel method. The orthorhombic crystal structure of the sample is confirmed by X-ray diffraction analysis. The electrical conductivity of BNMO is found to increase with frequency, indicating the presence of local charge carriers. The AC electrical conductivity follows Jonscher's equation, exhibiting a plateau at low frequencies and a power-law behavior at high frequencies. The activation energy for conduction is determined to be 0.654 eV. Impedance spectroscopy reveals the presence of grain and grain boundary contributions, which are modeled using an R-CPE combination circuit. Analysis of the electrical modulus demonstrates non-Debye type relaxation and indicates the presence of charge carrier hopping between Mn2+ and Mn3+ ions. The activation energy obtained from the relaxation peaks of the modulus is found to be 0.674 eV. The dielectric constant exhibits high values that increase with temperature. This observation suggests that the capacitance behavior holds promising potential for energy storage applications, making it a suitable candidate for various technological uses.

Modification on antibacterial activity of PVC/PVDF blend filled with CuO NPs using laser ablation technique

Nanocomposite of polyvinyl chloride (PVC)/polyvinylidene fluoride (PVDF) have been in situ synthesized. Copper oxide nanoparticles (CuONPs) have been prepared via using the laser ablation technique. Nanoparticles were added to the blend. The properties of the blend were studied before and after adding CuONPs. These properties were characterized by different techniques. Antimicrobial activity of the prepared nanocomposite film was investigated. FTIR data show vibrational spectral bands and the shift of the bands is related to the interaction and the complexation that occurs between blend and nanoparticles. Structural properties and crystallinity of the samples were investigated using XRD diffraction. XRD results illustrated the effect of CuONPs at two new peaks 2θ = 26.25º and 38.41º. These results confirmed the interaction CuO NPs and PVDF/PVC matrix. UV–Visible analyses confirmed the existing of copper oxide nanoparticles and were also used for determining the optical absorption edge. The absorption edges have been obtained at 430–520 nm for all of the doping films. The obtained values for indirect and direct bandgaps were reduced by raising the nanoparticles because of the presence of charge transfer between PVC/PVDF and CuONPs. SEM images illustrateed the presence of CuONPs on the surface of the blend and the morphology changes which occurred to the blend. The antibacterial activity for the nanocomposite proved the antimicrobial effect of copper oxide nanoparticles. The prepared PVC/PVDF/CuONPs are potentially suggesting to be applied for biomedical applications.

Electrical and room temperature multiferroic properties of polyvinylidene fluoride nanocomposites doped with nickel ferrite nanoparticles

The higher values of magneto-dielectric coupling is observed in flexible multiferroic polyvinylidene fluoride (PVDF) nanocomposites doped with nickel ferrite (NFO) nanoparticles.

Synthesis of CoFe Prussian blue analogue/poly vinylidene fluoride nanocomposite material with improved thermal stability and ferroelectric properties

Synthesis of a nanocomposite CoFe Prussian blue analogue (CoFePBA) molecular magnet with a polyvinylidene fluoride (PVDF) polymer show improved thermal stability and ferroelectric properties.

In situ synthesis and electromagnetic wave absorbing properties of sandwich microstructured graphene/La-doped barium ferrite nanocomposite

The development of high reflection loss and broad frequency bandwidth for electromagnetic wave absorbing materials has been pursued for a long time.