Dielectric and optical properties of Ni-doped LaFeO3 nanoparticles

Abstract

Un-doped and Ni-doped lanthanum ferrite nanoparticles were synthesized by solid-state method. Ni concentrationdependent structural, dielectric and optical properties of synthesized nanoparticles were investigated. X-ray diffraction patterns confirmed predominant single-phase orthorhombic crystal structure with space group Pbnm in all samples. Average crystallite size was found to vary from 19 to 21 nm with Ni concentration. The field emission scanning electron microscopy revealed nanocrystalline structure with homogenous distribution of particles. UV-Vis-NIR diffuse spectra captured at room temperature indicate that La 1−x Ni x FeO 3 is an indirect band gap material. The band gap varies from 1.70 to 1.85 eV with changing Ni concentration. Frequency-dependent dielectric constant, dielectric loss and ac conductivity were studied at room temperature. The dielectric constant was found to increase with increasing Ni content at high frequency. The loss factor resulted from domain wall resonance exhibited an identical dispersion behavior of dielectric constant. At high frequencies, the dielectric losses of orthoferrites were found to be low. This is attributed to the restricted motion of domain wall pointing its plausible practical applications in magnetically tunable filters and oscillators.

Mechanical behavior, enhanced dc resistivity, energy band gap and high temperature magnetic properties of Y-substituted Mg–Zn ferrites

“…The room temperature dc electrical resistivity (r RT ) of Mg 0.5 Zn 0.5 Y r RT is noted to increased due to Y substitution unlike for x=0.01 ( figure 8(a)), can be explained by Verwey mechanism based on electrons exchange involving the ions of the element with different valence states positioned octahedral (B-site) [79,80]. In the present case, the Fe 2+ and Fe 3+ is responsible for the conduction because of the hopping tendency between them [81,82] and the Fe 2+ ions are the product of sintering process [42]. The value of r RT is found to be 0.45×10 5 Ω cm for x=0.00 and 0.40×10 5 Ω cm, 1.57×10 6 Ω cm, 1.78×10 6 Ω cm, 2.19×10 6 Ω cm and 1.43×10 6 Ω cm for x=0.01, 0.02, 0.03, 0.04 and 0.05, respectively.…”

“…High resistivity of ferrites is essential for most electronic application and therefore, the study of dc electrical resistivity is important for prediction of their application in electronic and high In the present case, the Fe 2+ and Fe 3+ is responsible for the conduction because of the hopping tendency between them [83,84] and the Fe 2+ ions are the product of sintering process [42]. The value of 𝜌 𝑅𝑇 is found to be 0.45 × 10 5 Ω-cm for x = 0 and 0.40 × 10 5 Ω-cm, 1.57 × 10 6 Ω-cm, 1.78 × 10 6 Ω-cm, 2.19 × 10 6 Ω-cm and 1.43 × 10 6 Ω-cm for x = 0.01, 0.02, 0.03, 0.04 and 0.05, respectively.…”

Analysis of the effect of dielectric losses on the bandwidth of microstrip patch antenna in stacked geometry and modelling

“…Dependence, on both temperature and frequency, of both the dielectric constant (DK) and the dissipation factor (DF) has been already reported in many research papers [1,[6][7][8][9][10][11][12][13]. However, DK and DF in datasheets are average values (typical values).…”