ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Biocompatible K-substituted CoFe₂O₄ nanoparticles for electronics, energy, and biomedical uses: magnetic and physicochemical analysis

Ramprit Baitha, Anil Kumar Das, Sujit Kumar, Monalisa, and Aniket Manash

Mechanical Engineering Department, National Institute of Technology, Patna, India

E-mail: rampritb.nit@gmail.com

Received: 28 November 2025  Accepted: 17 February 2026

Abstract:

The impact of monovalent potassium (K⁺) substitution on the structural, magnetic, optical, electrical, luminescent, and ferroelectric properties of cobalt ferrite synthesized via an economical sol–gel process was systematically investigated in this study. The resultant nanomaterials exhibited a single-phase cubic spinel structure with good thermal stability and homogeneous crystallinity. XRD, FE-SEM, and FTIR analyses confirmed that the incorporation of K⁺ led to a reduction in crystallite size and modification of the grain morphology. Optical characterization revealed that variations in particle size and lattice distortion significantly influenced the band gap and photoluminescence behavior, suggesting the formation of defect states associated with potassium incorporation. Magnetic studies demonstrated enhanced saturation magnetization and coercivity while preserving soft magnetic behavior. Zeta potential and MTT assays confirmed good colloidal stability and cytocompatibility, indicating the material’s suitability for biomedical applications. Ferroelectric measurements further validated the material’s multifunctionality by exhibiting stable polarization characteristics. K⁺-doped cobalt ferrite thus emerges as a versatile functional nanomaterial owing to the simultaneous modulation of its structural, optoelectronic, magnetic, ferroelectric, and biocompatible properties. It offers significant potential for advanced applications in electronics, photocatalysis, magnetic devices, and biomedicine due to its tunable physicochemical characteristics. Overall, the enhanced magnetic response, controlled nanoscale morphology, and improved physicochemical stability achieved through potassium substitution render the synthesized cobalt ferrite nanoparticles highly promising candidates for advanced applications in spintronic devices, high-sensitivity magnetic sensing, and biomedical imaging.

Keywords: Ferrite; Monovalent; Structural; Optoelectronic; Magnetic; Ferroelectric

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04747-z

Chemical Papers 80 (6) 6025–6042 (2026)