Studies On Structural Morphological And Electrical Properties Of Potassium Based Brownmillerites For Electronic Application

Abstract

The diverse functionalities of dielectric materials have sparked significant research aimed at unraveling the fascinating physics behind these materials and creating custom-designed materials for potential technological use. The lead-based dielectric materials have proven effective in electrical devices, and their environmental and biological impacts raise substantial global concerns. This presents a major challenge for contemporary society, necessitating concerted efforts by materials scientists to develop lead-free devices that align with the goals of sustainable development.Among oxide perovskites, oxygen deficient perovskites has attracted significant interest in recent decades due to its distinctive properties. Detailed studies on potassium based materialreveals that a major limitation, such as low electrical resistivity and high dielectric loss, hindering its practical applications. newlineThis study focuses on the fabrication and structural and electrical characterization of potassium based Brownmillerites ceramics. In this work, the Fe-site in KBiFe2O5 is substituted with Mn3+ions to explore whether this modification improves properties such as resistivity, breakdown voltage, dielectric constant, resistive, and dielectric loss. Three Brownmillerite samples namely, KBiFe2O5 (KBFO), KBiMn2O5 (KBMO), and KBiFeMnO5 (KBFMO), were synthesized using a cost-effective high-temperature solid-state reaction method. Initial structural analysis using powder XRD revealed that the modified KBFO compounds adopt a monoclinic phase. Scanning electron microscopy showed a high-density, uniformly distributed grain structure across the sample surfaces. The effects of temperature and frequency on dielectric permittivity, dielectric loss, complex impedance, electric modulus, and electrical conductivity were analyzed across a wide frequency range (1 kHz 1 MHz) using complex impedance spectroscopy within the increase in temperature. The complex impedance spectra suggest that both grain and grain boundary effects contribute to the electri