Double perovskite compounds (DPCs) have gained much more attention due to their versatile character in the fields of electronics and spintronics. Using density functional theory (DFT) we investigated the electronic, magnetic and optical properties of DPC La₂BB′O₆ where B = Cr, Sc and V and B′ = Co, Ni. The electronic band gaps suggest these compounds are half-metallic (HF) semiconductors in the spin-up channel and metallic in the spin-down channel. Magnetic properties suggest these are ferromagnetic in nature, so all DPCs are half-metallic ferromagnetic (HM-FM). Furthermore, the compound La₂CrCoO₆ shows outstanding electronic and optical properties, so it can be used in optoelectronic/spintronic devices.

The objective of this study was to deposit thin films on PET polymer substrate and examine the functional properties systematically. Their properties have been studied as a function of the N₂-Ar flow rates, deposition time span and Cu doping. Iron nitride film deposited on both sides exhibits ferromagnetic phases, γ′-Fe₄N and ε-Fe₃N co-existed, shows negligible magnetic anisotropy. Other samples show the evolution of N-rich (FeN, Fe₂N) and N-poor (Fe₁₆N₂, Fe₃N, Fe₄N) phases under different deposition time conditions. XPS analysis and free energy calculations confirmed that co-sputtered Fe-Cu thin films are more stable than layer deposited counterparts. From VSM results it is evident that the dominant phase, changes steadily from the ferromagnetic α-Fe (N) to the paramagnetic ξ-Fe₂N with the increase of nitrogen flow rates and the ordering of the nitrogen atoms. Binding energy increases steadily from 733 eV to 740 eV with the increasing thickness of thin films from 74 nm to 94 nm. It was observed that surface energy decreases as the contact angle of glycol increases and changes the thin film surface from polar to nonpolar. TEM images indicate that cubic γ′-Fe₄N and ε-Fe₃N nano particles oriented in preferred directions dispersed uniformly in the amorphous iron nitride matrix.

We report the first results of functional properties of nitrogenized silver-permalloy thin films deposited on polyethylene terephthalic ester {PETE (C₁₀H₈O₄)_n} flexible substrates by magnetron sputtering. These new soft magnetic thin films have magnetization that is comparable to pure Ni₈₁Fe₁₉ permalloy films. Two target compositions (Ni₇₆Fe₁₉Ag₅ and Ni₇₂Fe₁₈Ag₁₀) were used to study the effect of compositional variation and sputtering parameters, including nitrogen flow rate on the phase evolution and surface properties. Aggregate flow rate and total pressure of Ar+N₂ mixture was 60 sccm and 0.55 Pa, respectively. The distance between target and the substrate was kept at 100 mm, while using sputtering power from 100–130 W. Average film deposition rate was confirmed at around 2.05 nm/min for argon atmosphere and was reduced to 1.8 nm/min in reactive nitrogen atmosphere. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, vibrating sample magnetometer, and contact angle measurements were used to characterize the functional properties. Nano sized character of films was confirmed by XRD and SEM. It is found that the grain size was reduced by the formation of nitride phase, which in turns enhanced the magnetization and lowers the coercivity. Magnetic field coupling efficiency limit was determined from 1.6–2 GHz frequency limit. The results of comparable magnetic performance, lowest magnetic loss, and highest surface free energy, confirming that 15 sccm nitrogen flow rate at 115 W is optimal for producing Ag-doped permalloy flexible thin films having excellent magnetic field coupling efficiency.

The dielectric constant of CCTO materials can be as high as 10⁴, which makes it suitable for use in electronic devices but the high dielectric loss limits its application. In this paper, a series of Sr and Zr co-doped CCTO ceramics having the formula Ca_0.8Sr_0.2Cu₃Ti_4−xZr_xO₁₂ (x = 0.1, 0.2, 0.3, 0.4) were obtained via a solid-state reaction technique. We force the effect of the Zr content on the phase composition, microstructure, cationic valence states, impedance, and dielectric properties of the as-prepared ceramics to reduce dielectric loss. The results demonstrate that Sr and Zr co-doping increases dielectric constant and reduces dielectric loss simultaneously, and the maximum dielectric constant (1.87 × 10⁵, 1 Hz) and minimum dielectric loss (0.43, 10² Hz) are obtained when x = 0.3. Mixed Cu⁺/Cu²⁺ and Ti³⁺/Ti⁴⁺ valence states are observed to coexist in the co-doped material lattices, which promote dipole polarization, and thereby increase the dielectric constant of the ceramics. The dielectric properties of the materials are analyzed according to the internal barrier layer capacitance model, which elucidates the contributions of the grains and grain boundaries to dielectric performance. The maximum grain boundary resistance (3.7 × 10⁵ Ω) is obtained for x = 0.3, which contributes toward the minimum dielectric loss (0.43) obtained for this ceramic at a frequency less than 1 kHz. The average grain sizes of the samples decrease with increasing Zr content, which is the primary factor increasing the grain boundary resistance of the co-doped ceramics.

Carbon-coated iron nitride nanoparticles were synthesized using ferrocene as the precursor material with an in-house manufactured microwave-plasma reaction system. XRD revealed that the nanoparticles contained mixed phases of iron nitride (FeN_0.0589 and ε-Fe₃N) and α-Fe. In the case of TEM, the powder displayed a core–shell structure with a core diameter of ∼15 nm and had a multilayer carbon structure. The particle sizes in all samples were 10–80 nm. The Raman spectra of the nanoparticles justified that the multilayer carbon coatings had an amorphous graphitic structure. The nanoparticles developed at an N₂ flow rate of 10 slpm yielded a superior Ms value of 37.2 emu g⁻¹. An increase in the N₂ flow rate exhibited a significant influence on the plasma temperature and reaction time, thereby affecting the composition of the mixed phase, the shape and size of the particles, and the uniformity and thickness of the carbon coating. This study provided a simple, efficient and economical method to prepare iron nitride magnetic nanoparticles, which is expected to be widely applied in industrial mass production.