Structural, magnetic and antibacterial studies of gadolinium doped cobalt ferrite nanoparticles synthesized at low temperature

In this work structural, magnetic and antimicrobial studies of gadolinium (Gd) doped cobalt ferrite nanopowder samples were synthesised through facile auto-combustion route using citric acid as combustion agent. The pristine nanopowders were sintered at 600 °C. X-ray diffraction (XRD), infrared spectroscopy (IR) measurements indicated the formation of a single spinel phase. The lattice constant gradually increased from 8.3801 Å to 8.3915 Å with increasing Gd concentration. The average crystallite size varied from 54 nm to 42.7 nm. The correlation between the cation distribution from XRD and the magnetic properties is discussed. The substitution of Gd ions significantly reduced the magnetisation from 60.6 to 36.6 emu g−1 and increased the coercivity. Antimicrobial activities of pure and Gd substituted cobalt ferrite are carried out against Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and also against fungi strain (Aspergillus niger) pathogens, suggesting that Gd substitution significantly improves the activity of cobalt ferrite nanopowders.