Narrowing of ferromagnetic resonance linewidth in calcium substituted YIG powders by Zr⁴⁺/Sn⁴⁺ substitution

Ca_x+yY_3−x−ySn_xZr_yFe_5−x−yO₁₂ powders were synthesized by a citric acid combustion method. The phase, microstructure and ferromagnetic resonance linewidth (ΔH) of the powders were analyzed. Pure garnet phase Y₃Fe₅O₁₂ could be obtained at 1,200 °C, except for YFeO₃ phase appearing in the sample with x = 0.5, y = 0.2. The addition of Zr⁴⁺ ion and Sn⁴⁺ ion could lower ΔH by replacing Fe³⁺ ion, which could change the a–d superexchange interaction in YIG lattice. Moreover, Zr⁴⁺ ion could promote this replacement by enlarging the lattice. However, too much addition of Zr⁴⁺ ion would bring the second phase YFeO₃. The sample of Ca_0.76Y_2.24Sn_0.7Zr_0.06Fe_4.34O₁₂ shows excellent properties which are M_s = 6.4 emu/g, H_c = 10.9 Oe, ΔH = 113 Gs.