Synthesis and characteristics of transparent Gd₂O₃ ceramics with cubic structure

Transparent Gd₂O₃ ceramics with a cubic crystal structure were successfully synthesized for the first time. The Gd₂O₃ ceramics subjected to hot isostatic press (HIP) at 1070 ℃ consisted of uniform grains of 2–3 μm, and only a few residual pores could be detected inside the materials. X-ray diffraction (XRD) shows that the obtained polycrystalline materials have a cubic crystal structure, and the transmission polarized light observation shows that there is no birefringence inside the materials, indicating inherent optical properties of the cubic crystal structure. The optical absorption edge is 640 nm (optical band gap: 2.1 eV), and the transmittance in the visible to near-infrared region is 72%, which is close to the theoretical transmittance calculated from Fresnel loss. Verdet constant of this material is almost wavelength-independent, and it is diamagnetic since it has the opposite polarity to that of common paramagnetic materials.