Magnetic Structured Nickel Core-Shell @ Silica/PMMA Nanocomposites from Synthesis to Applications

Incorporating Ni@SiO2 nanoparticles on poly-methyl methacrylate (PMMA) can alter electrical, optical, and magnetic properties of Ni nanoparticles to be used for energy storage applications, photo electronic devices and spintronic applications. The Ni@SiO2/PMMA nanocomposite samples are prepared by casting method. The morphology of the prepared nanoparticles was examined through high resolution transition electron microscope revealed the formation of SiO2 coating on ni nanoparticles. Furthermore, the topography of nanocomposites was characterized by the field emission scanning electron microscope. We investigated the formation of crystalline phase of Ni nanoparticles through X-ray diffraction. The Complex dielectric permittivity, electrical conductivity, electric modulus and impedance spectra of the PNC films were investigated in the frequency range from 0.1 Hz to 10 MHz. The real and imaginary parts of the permittivity decrease with increasing frequency due to an increase in Ni@SiO2 content. All the nanocomposites showed relatively low conductivity values and high impedance that could be used for nano-dielectrics. UV-Vis spectrophotometer was used to measure optical properties such as transmittance, and absorbance at normal incidence in the wavelength range of 200-1100 nm. The transmittance was found to decrease while the absorbance increases with increasing Ni@SiO2 nanoparticles. The indirect optical band gap of the composite films was calculated, and it was sharply decreased. Magnetic hysteresis plots at room temperature of composites Ni@SiO2/PMMA were studied. All samples demonstrate ferromagnetic behavior with well pronounced magnetic hysteresis.