A study on the tunable magnetic and magnetodielectric properties of KBFO-CFO composite

Multiferroic materials are very important in the current need for material science and multifunctional technological applications. KBiFe₂O₅ (KBFO) belongs to the brownmillerite family, which shows the weak magnetic and magnetodielectric coupling in the earlier report. To overcome these challenges, the present work focuses on synthesizing and characterization of polycrystalline multiferroic composites. In this regard, the parent material KBiFe₂O₅ (KBFO), CoFe₂O₄ (CFO), and its composites (1 − x)KBFO-(x)(CFO) where x = 0.1, 0.2, and 0.3 are synthesized using the citric-assisted sol–gel method. The composite’s magnetic, dielectric, and magnetodielectric properties are investigated over a wide temperature range (300 K to 873 K) to verify its magnetic and dielectric transitions. Observations include improved dielectric properties at 4.602 × 10⁶, enhanced magnetic coercivity at 1488.7955 ± 18.8897 Oe for the 0.8KBFO-0.2CFO composite, and remanent magnetization at 6.5899 ± 0.0551 emu/g for the 0.7KBFO-0.3CFO composite. We observed the enhanced magnetodielectric (MD) properties of the 0.8KBFO-0.2CFO composite at room temperature, which are ~ 3% in field-scanning mode and ~ 20% in frequency scanning mode. Switching MD coupling in the composite at room temperature can be important for applications involving spintronics, energy harvesting, and information storage devices.