# Systematic Evaluation of Zn2+, Ca2+, and Co2+ Doping for Tailoring the Thermal, Structural, Morphological and Magnetic Performance of CdBi0.1Fe1.9O4@SiO2 Nanocomposites

## TL;DR

This study explores how adding Zn2+, Ca2+, and Co2+ ions affects the properties of CdBi0.1Fe1.9O4@SiO2 nanocomposites, showing how these changes can be used to design materials for specific applications.

## Contribution

The paper systematically evaluates the effects of Zn2+, Ca2+, and Co2+ doping on the structural and magnetic properties of CdBi0.1Fe1.9O4@SiO2 nanocomposites.

## Key findings

- Doping and calcination temperature significantly influence the crystallization and phase formation of the nanocomposites.
- Co0.1Cd0.9Bi0.1Fe1.9O4@SiO2 forms a single crystalline phase, unlike other doped samples.
- Magnetic and structural properties can be tailored through controlled doping and thermal treatment.

## Abstract

The influence of Zn2+, Ca2+ and Co2+ doping on the thermal, structural, morphological, and magnetic characteristics of CdBi0.1Fe1.9O4 nanoparticles synthetized via the sol–gel technique and calcined at 300, 600, 900 and 1200 °C was investigated. Thermal analysis revealed the initial formation of metallic glyoxylates up to 300 °C, followed by their decomposition into metal oxides and subsequent ferrite formation. X-ray diffraction revealed that the ferrites were poorly crystallized at lower temperatures, whereas at higher calcination temperatures all nanocomposites exhibited well-crystalized ferrites coexisting with the SiO2 matrix, except for the Co0.1Cd0.9Bi0.1Fe1.9O4@SiO2 nanocomposite, which formed a single, well-defined crystalline phase. Atomic force microscopy images revealed spherical ferrite particles encapsulated within an amorphous layer, with particle size, surface area, and coating thickness influenced by both the type of dopant ion and the calcination temperature. The structural parameters estimated by X-ray diffraction, as well as the magnetic characteristics, were strongly influenced by the dopant type and thermal treatment. These results demonstrate that the structural and magnetic characteristics of CdBi0.1Fe1.9O4 ferrites can be effectively tuned through controlled doping and calcination, providing insights for the design of tailored functional applications.