Samples of the magneto-active material—Tb³⁺:Y₂O₃ ceramics with Tb³⁺ ion concentrations of 10%, 20%, 30%, and 100% (Tb₂O₃)—were prepared and studied. The wavelength dependence of Verdet constant in the 380 nm–1750 nm range was approximated for all investigated ceramic samples and was predicted for a pure Tb₂O₃ material. Tb₂O₃ ceramics demonstrates a more than three times higher Verdet constant in comparison with terbium gallium garnet crystal or ceramics. The linear dependence of the Verdet constant on Tb³⁺ ion concentration in the Tb³⁺:Y₂O₃ ceramics was demonstrated. The obtained data will be useful for fabricating magneto-optical elements of Faraday devices based on Tb³⁺:Y₂O₃ with arbitrary Tb³⁺ ion concentration operating at room temperature in the wavelength range of 380 nm–1750 nm.

The method of self-propagating high-temperature synthesis of submicron powders with subsequent vacuum sintering was used to produce a series of optical ceramics based on dysprosium oxide $({\mathrm{Dy}}_x{\mathrm{Y}}_{0.95-x}{\mathrm{La}}_{0.05}{)}_2{\mathrm{O}}_3$, where $x=0.7$, 0.85, and 0.9. The influence of ceramics composition on optical transmission of the obtained samples was investigated. The studied materials had several transparency windows in the visible 500–730 nm, near-IR 1900–2300 nm, and mid-IR 3500–7500 nm ranges. The dependence of the Verdet constant on wavelength in the 400–1940 nm range was measured for each ceramics composition, and analytical approximations were obtained. When Y and La dopants were used, the Verdet constant depended linearly on the concentration of ${\mathrm{Dy}}^{3+}$ ions, and its value in the visible wavelength range was about twice that of the analogous value for a terbium gallium garnet crystal. The high transmission and relatively high Verdet constant make the produced materials highly promising for fabricating Faraday devices for ${\mathrm{Tm}}^{3+}$ and ${\mathrm{Ho}}^{3+}$ lasers and for lasers emitting in the visible spectrum.

A glycine-nitrate self-propagating high-temperature synthesis (SHS) was developed to produce composite MgO-Gd₂O₃nanopowders. The X-ray powder diffraction (XRD) analysis confirmed the SHS-product consists of cubic MgO and Gd₂O₃phases with nanometer crystallite size and retains this structure after annealing at temperatures up to 1200 °C. Near full dense high IR-transparent composite ceramics were fabricated by spark plasma sintering (SPS) at 1140 °C and 60 MPa. The in-line transmittance of 1 mm thick MgO-Gd₂O₃ceramics exceeded 70% in the range of 4–5 mm and reached a maximum of 77% at a wavelength of 5.3 mm. The measured microhardness HV0.5 of the MgO-Gd₂O₃ceramics is 9.5±0.4 GPa, while the fracture toughness (K_IC) amounted to 2.0±0.5 MPa·m^1/2. These characteristics demonstrate that obtained composite MgO-Gd₂O₃ceramic is a promising material for protective infra-red (IR) windows.