The role of Dy3+ ions and sintering temperature on the magnetic characterization of LiCo-Ferrite

Magnetic and magnetostrictive behavior of Dy3+ doped CoFe2O4 single crystals grown by flux method

“…At 300 K the observed M s is 3.21 mB/f.u or equivalently 73 emu/g; this value is in agreement with the reported data for the corresponding polycrystalline and single crystal cobalt ferrite [21,29,30]. However, the observed values of M s and H c are found to be smaller than pure cobalt ferrite single crystal [21], this is because of the replacement of Fe 3 þ (ferromagnetic) by Dy 3 þ (paramagnetic) in the cobalt ferrite lattice [10,13,24]. At 300 K the present Co-Fe-Dy single crystal exhibits moderate saturation magnetization (73 emu/g) and low coercivity $ 23 Oe, which signifies its applicability for magnetooptic recording media as it requires moderate saturation magnetization and low hysteresis loss.…”

“…For devices that require low-power light sources, pure cobalt ferrite is unsuitable because of its large coercivity and Curie temperature, which should be minimized. This can be readily achieved by a para/diamagnetic substitution of Fe 3 þ ions in CoFe 2 O 4 such as some lanthanide ions [9,[12][13][14].…”

Effect of cation distribution on structural and magnetic properties of Dy substituted magnesium ferrite

“…This anomalous behavior of magnetization may be due to the formation of secondary phase i.e., DyFeO 3 (non-magnetic) phase as explained in x-ray diffraction analysis. Such type of behavior is also reported in some Al 3 þ [11] and Dy 3 þ substituted Mg-ferrite and Li-Co ferrite [20], respectively. Pradhan et al [6] showed that the magnetic properties of MgF are strongly dependent on the cation distribution among tetrahedral (A) and octahedral (B) sites in the cubic type-spinel structure, where the structure formula of Mg-ferrite is usually written as…”

“…So, the decrease in magnetization can be attributed to the replacement of Fe 3 þ (0.64Å) by Dy 3 þ (0.99Å) on the octahedral sites which is mainly responsible for magnetization. The increase in magnetization for x¼3 and 5% of Dy substitution might be due to replacement of Fe with effective magnetic moment, m eff ¼5.85 BM by Dy with effective magnetic moment m eff ¼10.50 BM [20,36], which in turn rises the resultant effective magnetic moment m eff . In case of 7% of Dy concentration, the drop in the magnetization may be due to the quenching of the orbital momentum leaving the spins to be the only effective parameter [20].…”

“…The effect of metal ion substitution such as Al [10,11], Ge [12], Cu [13], Ni [14], Cr [15], Sm-Gd [16], Ce-Gd [17] on the magnetic properties of MgFe 2 O 4 has been reported in the literature. The effect of dysprosium substitution in various ferrites such as NiFe 2 O 4 [18], Mn-Zn ferrite [19], Li-Co [20] and manganese ferrite [21] has also been reported in the literature. To the best of author's knowledge, there is no such report on the effect of Dy 3 þ cation distribution on the structural and magnetic properties of MgDy x Fe 2 À x O 4 where (x ¼0.0, 0.01, 0.03, 0.05, 0.07).…”