Influence of La doping and synthesis method on the properties of CoFe2O4 nanocrystals

• CoLaxFe2−xO4 nanocrystals crystallized in spinel cubic structure using 3 techniques.
• The decrease in the lattice constant is due to the difference in ionic radius of La+3 and Fe3+.
• The citrate method exhibit largest values of Ms amongst all techniques.
• Coercivity exhibits largest values for citrate and then flash, smallest for ceramic technique.

Nanocrystals of La doped CoFe2O4 were synthesized using three different techniques: flash autocombustion, citrate–nitrate and the standard ceramic technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the obtained nanocrystals. All samples were crystallized in a spinel structure with cubic symmetry. The decrease in the lattice constant was endorsed to the large difference in ionic radii of both La+3 (1.216 Å) and Fe (0.65 Å) in 6-f coordination. The citrate method displayed superior Ms values amongst all techniques. The coercivity was found to exhibit largest values for the citrate method and then the flash while smallest values are associated with ceramic technique.