CoY_xFe_1.98-xO₄, x = 0; 0.1; 0.2; 0.3, were prepared by sol-gel.

A slight iron deficiency in the formulation was designed to improve Y solubility.

Yttrium enters the lattice in octahedral sites.

Ms and Tc decrease with iron substitution, confirming the B site occupancy of Y ions.

Y inclusion modifies Raman spectra, and new vibrational modes appear.