In this study we fabricated, for the first time, magnesium gallate (MgGa2O4, a partially inverted spinel) transparent ceramics, both undoped and doped with 1 at% Ni. The specimens were derived from in-house prepared powder, with a crystallite size of ∼10 nm (by wet chemistry) and densified by pulsed electric current sintering (PECS; peak temperature 950 °C for 90 min). Densification levels of 99.84% and 99.52% of theoretical density were attained for doped and undoped materials, respectively. Doping with Ni was seen to marginally improve the densification level. Quite transparent specimens were produced: the best showing transmission of ∼89% of the theoretical level (thickness t = 0.85 mm). The absorption spectra revealed that the dopant was accumulated as Ni2+ in the octahedral sites of the lattice, as occurs in single-crystal specimens. After excitation at 980 nm, the doped disks exhibited a wide fluorescence band centered at 1264 nm.

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Mixtures of Ce-doped rare-earth aluminum perovskites are drawing a significant amount of attention as potential scintillating devices. However, the synthesis of complex perovskite systems leads to many challenges. Designing the A-site cations with an equiatomic ratio allows for the stabilization of a single-crystal phase driven by an entropic regime. This work describes the synthesis of a highly epitaxial thin film of configurationally disordered rare-earth aluminum perovskite oxide (La 0.2 Lu 0.2 Y 0.2 Gd 0.2 Ce 0.2 )AlO 3 and characterizes the structural and optical properties. The thin films exhibit three equivalent epitaxial domains having an orthorhombic structure resulting from monoclinic distortion of the perovskite cubic cell. An excitation of 286.5 nm from Gd 3+ and energy transfer to Ce 3+ with 405 nm emission are observed, which represents the potential for high-energy conversion. These experimental results also offer the pathway to tunable optical properties of high-entropy rare-earth epitaxial perovskite films for a range of applications.

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Silica glasses have wide applications in industrial fields due to their extraordinary properties, such as high transparency, low thermal expansion coefficient, and high hardness. However, current methods of fabricating silica glass generally require long thermal treatment time (up to hours) and complex setups, leading to high cost and slow manufacturing speed. Herein, to obtain high‐quality glasses using a facile and rapid method, an ultrafast high‐temperature sintering (UHS) technique is reported that requires no additional pressure. Using UHS, silica precursors can be densified in seconds due to the large heating rate (up to 102 K s−1) of closely placed carbon heaters. The typical sintering time is as short as ≈10 s, ≈1–3 orders of magnitude faster than other methods. The sintered glasses exhibit relative densities of > 98% and high visible transmittances of ≈90%. The powder‐based sintering process also allows rapid doping of metal ions to fabricate colored glasses. The UHS is further extended to sinter other functional glasses such as indium tin oxide (ITO)‐doped silica glass, and other transparent ceramics such as Gd‐doped yttrium aluminum garnet. This study demonstrates an UHS proof‐of‐concept for the rapid fabrication of high‐quality glass and opens an avenue toward rapid discovery of transparent materials.

High‐entropy ceramics have been widely explored and extensively studied since the first demonstration of the configuration entropy stabilized reversible transitions between multiple and single phases by Rost et al. in 2015. Most of the current research on high‐entropy ceramics has focused on properties like thermal conductivity, thermoelectricity, structures, and others. Some recent studies have extended the high‐entropy concept to the field of transparent ceramics. We reviewed these papers and proposed four potential ceramics groups for high‐entropy transparent ceramics including fluoride ceramics, fluorite‐deficient and/or ordered pyrochlore A2B2O7 ceramics, garnet ceramics, and sesquioxide ceramics. In this article, we review ceramic powder synthesis, the fabrication of transparent ceramics, high‐entropy ceramics, and limited cases of high‐entropy transparent ceramics for each category. High‐entropy transparent ceramics with diverse compositions and structures will provide more possibilities for functional transparent ceramics in the future.