On magnetic moment of Cr^{3+} ion in ferrites-chromites with spinel structure

The behaviour ofthe paramagnetic susceptibllity ofa series offerrites-chromites samples with а high content of Cr$^{3+}$ ions has been studied. The experimental value of the Curie-Weiss constant has been found to bе much smaller than the theoretical one on the basis of the obtained results and making use of the results of NMR study in the compound MgO with an admixture of Cr$^{3+}$ ions. For the first time the authors have made а proposal that the understated values of the experimental magnetic moments of ferrites-chromites with а high content of chromium ions may also bе due, together with other reasons, to а decrease in the magnetic moment of Cr$^{3+}$ $({t^3}_{2g},{e^0}_g)$ ions because of the transfer of the spin density from О$^{2-}$ ions to the vacant eg-orbltals of Cr$^{3+}$ ions.