Impact of erbium substitution on structural, dielectric, spectral, and microwave absorption properties of Ba3Co2Fe24O41 Z-type hexa-ferrites for microwave devices applications

Abstract

A series of erbium-substituted Z-type hexaferrites with composition Ba3Co2ErxFe24-xO41 (0.00≤ x ≤ 0.12, Δx = 0.03) was synthesized via the sol-gel auto combustion technique and sintered at 1200 °C for 5:30 h. XRD analysis confirmed the single phase crystals throughout the samples. Incorporating erbium ions into a Z-type hexagonal lattice showed improved structural parameters. The lattice parameters (a, c) exhibited an increasing trend with the rare earth (Erbium) substitution in the range of 5.884–5.891 nm and 52.561–52.770 nm. Scherrer's equation was used to find crystallite size in 28–30 nm range. Absorption bands of ferrite phase were confirmed by Fourier Transform Infrared Spectroscopy. Dielectric characteristics of synthesized materials were studied through Epsilometer R60 VNA over a frequency 1 MHz to 6 GHz range. Variations in dielectric parameters were observed by substituting erbium ion into a Z-type hexaferrite lattice. The magnitude of the dielectric constant, AC conductivity, tangent loss, and dielectric loss increases at higher frequencies. While, dielectric constant, AC conductivity, loss factor, and tangent loss decrease with Erbium substitution. The high value of Q-factor ∼10232 at 0.87 GHz was observed. The cole-cole plots in impedance analysis confirmed the character of grains and grain boundaries in the conduction mechanism. Minimum reflection loss (RL) was −67 dB for the sample x = 0.06 at 0.2 GHz. At 1.28 GHz frequency, RL = −46 dB was observed for sample x = 0.03. The morphological study (SEM) revealed the hexagonal platelet-type grains with an average grain size of 2.48–2.73 μm. Minimum reflection loss, small crystallite size <50 nm, and high-quality factor suggested that these materials are suitable candidates for microwave absorbers, resonant circuits, multi-layer chip inductors, and high-frequency devices.