Enhanced electrical transport properties of Cr-substituted Mg2–Y-type hexaferrites for power applications

• Published in: Ceramics international 2023-10, Vol.49 (20), p.32588-32599
• Main Authors: Arshad, Muhammad, Khan, Muhammad Azhar, Rasool, Raqiqa Tur, Arshad, Muhammad Imran, Irfan, M.
• Format: Article
• Language: English
• Subjects: Cole-cole plots; Electrical resistivity; FTIR; High-frequency power applications; XRD; Y-type hexaferrites
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2023.07.225

The impact of Cr3+ substitution on the electrical and dielectric properties of Y-type hexaferrites with composition Ba2Mg2CrxFe12-xO22 (x = 0.0, 0.5, 1.0, 1.5, and 2.0) was synthesized by the sol-gel auto combustion technique. The lattice parameters 'a' and 'c' slightly increase with the substitution content of Cr3+, and some other physical parameters, including porosity, microstrain, dislocation density, specific surface area, and stacking fault coefficient, were determined from XRD data. FTIR spectra confirm the formation of iron oxide base material by the appearance of three signature bands at precisely 429, 474, and 499 cm-1 due to Fe–O vibrations at octahedral and tetrahedral sites. Substituting Cr3+ at the octahedral site enhanced the room temperature DC electrical resistivity from 6.89 × 109 to 2.27 × 1010 Ω-cm. Temperature-dependent DC electrical resistivity exhibits semiconducting behavior. There is a direct relation between resistivity and activation energy. The dielectric behavior of Cr3+ substituted samples in the frequency range of 1 MHz–6 GHz was understood based on the conduction mechanism through the hopping of electrons between Fe3+ and Fe2+ ions and the Maxwell-Wagner Model. In impedance spectroscopy studied using Cole-Cole plots, most dielectric response arises from the contribution of the grain boundary effect. With the substitution of Cr3+, dielectric losses decreased. A very high Q-value around 1 GHz was observed, suggesting that these hexaferrites are efficient materials for many high-frequency applications, such as multi-layer chip inductors (MLCI), dielectric resonators, and power applications.