Effect of Cr3+ ions on the magnetic moment of ferrites of the system CuFe2−xCrxO4

The dependence of the magnetic moment n0exp of samples of the system CuFe2−xCrxO4 (x=0.0, 0.2, 0.3, 1.0, 1.4, 1.6, and 2.0) on their Cr3+ content is examined here for the first time. It is found that the experimental values of the magnetic moment n0exp are much smaller than the values calculated from the cation distribution obtained previously (n0 theor). It is suggested that this relationship (n0 theor>n0 exp) is due to a decrease in the magnetic moments of the Cr3+ ions resulting both from pairing of the t2g orbitals of these cations in the octahedral sublattice and from a transfer of spin density from the ligands to the eg orbitals of these ions. For compositions with x>1.0, the noncollinear magnetic structure also leads to an increase in the difference between n0 theor and n0exp.