Dy-Cu-Sn Triple-Doped Yttrium Iron Garnet: Enhanced Magnetism and Dielectrics for Microwave Devices

Yttrium iron garnet (YIG), a typical ferrimagnetic oxide with unique spin-wave properties, is widely used in microwave and optoelectronic applications due to its strong Faraday rotation, low optical loss, and high Curie temperature. In this work, Dy-Sn-Cu tridoped YIG ceramics with the composition Y_3-x Dy _x Fe_4.8Cu_0.1Sn_0.1O₁₂ (x = 0.05-0.20) were synthesized via solid-state reaction. By regulating the Dy³⁺ doping concentration, a synergistic optimization of the microstructure, crystal structure, magnetic, and dielectric properties was achieved. Results indicate that Dy ions preferentially substitute at the dodecahedral c-sites, leading to lattice expansion, grain growth, and densified microstructure. At x = 0.15, the material exhibits optimal soft magnetic performance with a saturation magnetization of 28.42 emu/g, a coercivity of 5.39 Oe, and a real permeability of 78.92 at 1 MHz. The enhancement is primarily attributed to strengthened superexchange interactions and reduced domain wall pinning. Dy doping increases magnetic anisotropy, resulting in a broadened ferromagnetic resonance line width from 69 to 195 Oe. At x = 0.20, the dielectric constant reaches 20.34, dielectric loss decreases to 0.13, and electrical resistivity rises to 3.34 × 10⁹ Ω cm at 305 K. This study offers a viable strategy for developing high-performance, compact, and efficiently integrated microwave components.