Contribution of Fe²⁺, Mn³⁺and Fe³⁺ions to the magnetic anisotropy of MgxMn0.6Fe2.4-xO₄

The temperature dependences of the saturation magnetization sigma s and of the anisotropy K 1 were measured in single crystals of Mg x Mn y Fe 3-x-y O 4 , 0<or=x<or=0.63, y approximately=0.6. The magnitude and temperature dependence of the anisotropy contributions H 1 of Fe 2+ , Mn 3+ and Fe 3+ ions in B sites were found. The values H 1 (=K 1 per ion) established close to 0K are H 1 (Fe 2+ )=0.21 7 cm -1 per ion, H 1 (Mn 3+ )=-0.37 7 cm -1 per ion and H 1 (Fe 3+ )=-0.05 cm -1 per ion. From the experimental results it follows that in B sites of the spinel investigated, the ground state of the Fe 2+ ion is a singlet, the first excited state is a doublet, and the energy separation between singlet and doublet levels is E t =(1770+or-150) cm -1 .