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( x )BaTiO 3 –(1− x )Co 0.7 Fe 2.3 O 4 (BTO-CFO) magnetoelectric nanocomposite ceramic with x = 0.0, 0.25, 0.50, 0.75, 1.00 were successfully designed and fabricated by sol-gel route. The structural, micro structural, dielectric, ferromagnetic, ferroelectric and magnetoelectric properties of these composites were investigated. The coexistence of tetragonal phase and cubic spinel phase, without any secondary phase in composites is confirmed by the X-ray diffraction measurement. The field emission scanning electron micrograph show well distributed ferrite and ferromagnetic phases in the composites. The energy dispersive X-ray results revealed the purity and stoichiometry of BTO-CFO nanocomposites. The dielectric constant and loss factor of the composites were studied as a function of frequency. The composite sample with x = 0.50, results in higher value of dielectric constant whereas CFO possess lowest value of dielectric constant. The magnetization hysteresis (M−H) loop of the composites show ferromagnetic behavior with saturation magnetization values, Ms varies from 15 to 67.68 emu/g and coercive field Hc from 1538 to 1862 Oe. All the composites exhibit typical ferroelectric hysteresis loops indicating the presence of spontaneous polarization. The magnetoelectric voltage coefficient increases linearly with increases in applied d.c. magnetic bias field up to 8 KOe. The maximum value of magnetoelectric voltage coefficient, α ME = 7.7 mV/cm Oe for BTO-CFO composite having 25% ferrite and 75% ferroelectric content. The high ME voltage coefficient of BTO-CFO composite may be suitable for storage device application.

The magnetoelectric (ME) nanocomposite material contain ferromagnetic phase of yttrium iron garnet (Y3Fe5O12) and ferroelectric phase of yttrium perovskite ferrite (YFeO3) with an equation (x)YFeO3 + (1 − x)Y3Fe5O12 (x = 0.0, 0.25, 0.50, 0.75, 1.0) is synthesized by sol–gel auto combustion method. The composite powder obtained by two phases of composite material sintered at 1100 °C for 6 h. The prepared samples were investigated by using powder X-ray diffraction (XRD) to study the structural properties, that confirm the existence of two phases of Y3Fe5O12 and YFeO3. The crystallite size of material decreased from 23 to 13 nm with increasing the concentration of YFeO3 in composite. The morphological investigation of samples was studied by field emission scanning electron microscopy that gives size, shape and distribution of grains in material and confirmed that material has nano-crystalline in nature. Saturation magnetization (Ms) studied by using vibrating sample magnetometer shows the decrement in its value from 23.9 to 0.48 emu/g with the increase in YFeO3 content. Maximum magnetoelectric coefficient (αME) of 10.711 mv/cm-Oe is observed for composition x = 0.50. Similarly, ferroelectric characteristics of sample such as dielectric constant and dielectric loss were measured in the frequency range 20 Hz to 10 MHz at room temperature. The value of dielectric constant is decreases with increasing frequency and ferroelectric hysteresis loop at room temperature is study by using P-E loop tracer it’s nature is unsaturated due to presence of Y3Fe5O12 phase.

Effect of swift heavy ions (SHI) on low-k SiO2 thin films has been investigated. SiO2 thin films were deposited on pre-cleaned p-Si substrate by using sol-gel spin coating technique. Further, deposited films were annealed at 400 ∘C to remove structural irregularities. Prepared samples were irradiated with 200 MeV Ag15+ ions at different ion fluence such as 5 × 1011, 1 × 1012 and 5 × 1012 ions/cm2. Deposition of SiO2 was confirmed by using EDAX and FTIR spectroscopy. Increase in ion fluence increases the RMS roughness from 1.49 to 7.79 nm. The transformation of deposited material from polycrystalline to amorphous nature was confirmed from XRD spectra. Increase in SHI fluence decreases the grain size from 181.3 to 74.1 nm for pristine and sample irradiated at 5 × 1011 ions/cm2. Whereas, for sample irradiated with 5 × 1011 ions/cm2 fluence doesn’t show crystalline peak at (011). It is observed that SHI irradiation leads to grain agglomeration with decrease in crystal size at higher fluence. Further, conductivity of the samples under study was observed to be decreased with increase in ion fluence. Thus, it is demonstrated that the surface and structural properties of low-k silica thin films can be tailored by controlling the SHI fluence.

The non-ionic surfactant polysorbate 80 (Tween-80) based single step HF assisted mesoporous low-k films were synthesized by using sol–gel spin coating technique. The obtained films were annealed at 150 °C for 1 h to remove the added porogen and the pore solvents. Film thickness and refractive index were measured by spectral ellipsometry and changes in chemical compositions were investigated by using FTIR spectroscopy. The formation of SiO2 in film matrix and incorporation of low polar bonds like F and C were confirmed from obtained FTIR spectra. The porous nature of deposited film was confirmed from FE-SEM micrograph and the measured average pore diameter of mesopores was found to be 16.54 nm. The highest porosity percentage of 60.74% was obtained for the annealed sample deposited with 1 ml of Tween-80 in coating solution. The measured RMS roughness of the samples before and after annealing was observed to be increased from 0.029 to 0.079 nm. The lowest dielectric constant extracted from C–V curve measurement is of 1.06. These obtained mesoporous films with lower k value of 1.06 may be a suitable candidate as interlayer dielectric (ILD) for back end of line (BEOL) in CMOS technology.

Low dielectric constant (Low-[Formula: see text]) films are used as inter layer dielectric (ILD) in nanoelectronic devices to reduce interconnect delay, crosstalk noise and power consumption. Tailoring capability of porous low-[Formula: see text] films attracted more attention. Present work investigates comparative study of xerogel, aerogel and porogen based porous low-[Formula: see text] films. Deposition of SiO2 and incorporation of less polar bonds in film matrix is confirmed using Fourier Transform Infra-Red Spectroscopy (FTIR). Refractive indices (RI) of xerogel, aerogel and porogen based low-[Formula: see text] films observed to be as low as 1.25, 1.19 and 1.14, respectively. Higher porosity percentage of 69.46% is observed for porogen-based films while for shrinked xerogel films, it is lowered to 45.47%. Porous structure of low-[Formula: see text] films has been validated by using Field Emission Scanning Electron Microscopy (FE-SEM). The pore diameters of porogen based annealed samples were in the range of 3.53–25.50 nm. The dielectric constant ([Formula: see text]) obtained from RI for xerogel, aerogel and porogen based films are 2.58, 2.20 and 1.88, respectively.

The present work is focused towards the lowering of the k value of deposited SiO2 thin films by varying solvent concentration i.e. ethanol in the range 4-10 ml. Porous low-k thin films were synthesized by using the sol-gel spinon technique. A non-ionic surfactant polysorbate 80 (Tween 80) was used as a porogen to generate the porosity in the film matrix. The lower values of refractive index and film density were measured to be 1.19 and 0.94 gm/cm3 respectively for 10 ml solvent concentration. Further, the lowest k value of 2.2 and highest porosity percentage of 58.5 % were obtained for the same film due to the dilution of coating solution at higher solvent concentration. The water contact angle of the film was observed to be increased to 106.3° which indicates the transformation of the deposited film surface from hydrophilic to hydrophobic. The change in chemical structure as an effect of solvent concentration is studied by using FTIR. From FTIR spectra the disappearance of Si-OH groups at higher solvent concentration reveals the increase in condensation rate. Overall in this study, the result shows the significant change in structural, chemical and optical properties of the deposited films at 10 ml solvent concentration. Such deposited porous thin films with lower k value and enhanced hydrophobicity can be used as an interlayer dielectric (ILD) for back end of line (BEOL) in CMOS technology.