A cost-effective approach to fabricate (1-x)KBiFe2O5-(x)CoFe2O4 multiferroic composites prepared via citric-assisted sol-gel method

This article investigates temperature-dependent magnetic, dielectric, and magnetoelectric (MD) properties of KBiFe₂O₅(KBFO)-CoFe₂O₄(CFO) composite, synthesized via the citric-assisted sol-gel method. The addition of CFO reduces the average grain size from 2.01 µm (KBFO) to 0.23 µm (0.7KBFO-0.3CFO). As the temperature declined, the improved M_R and H_C changes from 0.3768 ± 0.0018 to 0.8726 ± 0.0018 μ_B/f.u. for 0.7KBFO-0.3CFO and 1196.3167±5.1481 to 20,986.7336±37.2229 Oe for 0.8KBFO-0.2CFO, respectively. The improved dielectric permittivity introduces a pronounced MD response. The dielectric permittivity at 300 K increased significantly from 35 (KBFO) to 155 in the 0.8KBFO-0.2CFO composite. In ±1.3T magnetic field, KBFO shows nearly 3.2 % MD coupling. However, the 20 % incorporation of CFO improves coupling to ∼17 %. Observed MD coupling involves a combination of Maxwell-Wagner polarization and dipolar relaxation. The significant dispersion at low temperatures suggests the presence of dielectric relaxation phenomena. In our finding, 0.8KBFO-0.2CFO is recommended as a sustainable multiferroic composite for low-energy data storage and information processing from cryogenic to RT and above.