Comparative study of structure and magnetic properties of micro- and nano-sized GdxY3−xFe5O12 garnet

• Aiming to enhance the magnetic properties for (GdxY3−xFe5O12), it was prepared by two methods for comparing, the standard ceramic and the co-precipitation method.
• The saturation magnetization (Ms) is found to be higher in samples prepared by (SC) method than ones prepared by (CP) method.
• The coercivity is found to increase with Gd+3 concentration for both systems; the values of Hc are few tens of oersteds which make them promising materials for soft magnetic applications at high frequency.
• (μi) and (Tc) are higher in samples prepared by (SC) method than ones prepared by (CP) method.
• The magnetic loss was measured for all investigated samples, which increased with increasing Gd concentration. Furthermore, it was found that the samples prepared by (SC) method have magnetic loss higher than those prepared by (CP) method.

Gadolinium Yttrium Iron garnet (GdYIG) samples with the chemical formula (GdxY3−xFe5O12) (x=0.0, 0.25, 0.5, 0.75, and 1.0) were prepared via two different methods, the standard ceramic method (SC) and the co-precipitation method (CP). The effect of preparation conditions and Gd3+ ion substitution on the phase formation, crystal structure, morphology and magnetic properties were studied. Moreover, the initial permeability μi and Curie temperature Tc were measured for all investigated samples. It was found that, the lattice parameter increases on addition of Gd3+ ion while the porosity decreases for both systems of samples. The crystallite sizes of the samples prepared by the (CP) method are smaller than those prepared by (SC) method. The magnetization Ms decreases while the coercivity Hc increases by increasing the Gd+3 concentration in both systems of samples. For the samples prepared by the (SC) method the values of Ms are higher than those prepared by (CP) method. Also, it was found that the initial permeability μi and Curie temperature Tc are higher in samples prepared by (SC) method than those prepared by (CP) method. Moreover the magnetic loss (the rate of temperature raise (ΔT/Δt) in an AC magnetic field) was measured for all investigated samples, which increased with increasing Gd concentration. Furthermore, it was found that the samples prepared by (SC) method have magnetic loss higher than those prepared by (CP) method.It was concluded that the preparation method has great effects on the magnetic properties of GdYIG ferrite. The obtained results were explained in the light of Neel's model.