A dielectric ceramic composition includes a base material main component of barium titanate and a subcomponent. A microstructure of the dielectric ceramic composition after sintering includes a first grain having a Ca content of less than 3.5 at % and a second grain having a Ca content of 3.5 to 13.5 at %, and an area ratio of the second grain to an area of the total grains is 70% to 95%.

A preparation method and use of a green fluorescent transparent ceramic are disclosed. The preparation method includes: weighing, according to a stoichiometric ratio, elements present in Ca.sub.3-x-yCe.sub.xA.sub.ySc.sub.2-xB.sub.zSi.sub.3-mC.sub.mO.sub.12, in forms of oxides, carbonates or nitrates as raw materials; mixing the raw materials, annealing, melting at a high temperature, cooling and annealing at a low temperature; putting the glass into a high-temperature furnace, holding, raising the temperature, and performing crystallization and densification sintering; finally cutting, reducing and surface-polishing, where A is at least one from the group consisting of Lu, Y, Gd, La and Na; B is at least one from the group consisting of Zr, Hf and Mg; C is at least one from the group consisting of Al and P; x, y, z and m satisfy 0.001≤x≤0.06, 0≤y≤0.06, 0≤z≤0.06 and 0≤m≤0.3, respectively.

A dielectric ceramic composition and a multilayer ceramic capacitor including the same are provided, the dielectric ceramic composition includes a BaTiO.sub.3-based base material main component and a subcomponent, wherein the subcomponent includes zinc oxide (ZnO) as a first subcomponent, and the content of the ZnO is 0.1 mol % or more and less than 0.4 mol % with respect to 100 mol % of the base material main component.

A method for fabricating a composite useful in a white light emitting device, includes mixing a phosphor and a filler to form a mixture; sintering the mixture (e.g., using spark plasma sintering) to form a composite; and annealing the composite to reduce oxygen vacancies and improve optical properties of the composite. Also disclosed is a white light emitting device including a laser diode or light emitting diode optically pumping the phosphor in the composite to produce white light. The composite fabricated using the method (and having. e.g., at most 50% phosphor by weight) can (1) reduce an operating temperature of the phosphor by 55 degrees, (2) increase an external quantum efficiency (e.g., by at least 15%) of the white light emitting device, and (3) result in color points and quality of the white light that is equal to or improved, as compared to without the filler.

A dielectric ceramic composition and a multilayer ceramic capacitor including the same are provided. The dielectric ceramic composition includes a BaTiO.sub.3-based base material main ingredient and an accessory ingredient, where the accessory ingredient includes dysprosium (Dy) and niobium (Nb) as first accessory ingredients. A total content of the Dy and Nb is greater than 0.2 mol and less than or equal to 1.5 mol based on 100 mol of titanium (Ti) of the base material main ingredient.

In an embodiment a conversion element includes a first phase and a second phase, wherein the first phase comprises lutetium, aluminum, oxygen and a rare-earth element, wherein the second phase comprises Al.sub.2O.sub.3 single crystals, and wherein the conversion element comprises at least one groove.

A multilayer ceramic capacitor includes: a ceramic body in which dielectric layers and first and second internal electrodes are alternately stacked; and first and second external electrodes formed on an outer surface of the ceramic body and electrically connected to the first and second internal electrodes, respectively. In a microstructure of the dielectric layer, dielectric grains are divided by a dielectric grain size into sections each having an interval of 50 nm, respectively, a fraction of the dielectric grains in each of the sections within a range of 50 nm to 450 nm is within a range of 0.025 to 0.20, and a thickness of the dielectric layer is 0.8 μm or less.

A dielectric ceramic composition and a multilayer ceramic capacitor comprising the same are provided. The dielectric ceramic composition includes a BaTiO.sub.3-based base material main ingredient and an accessory ingredient, where the accessory ingredient includes dysprosium (Dy) and cerium (Ce) as first accessory ingredients. A total content of Dy and Ce is greater than 0.25 mol % and equal to or less than 1.0 mol % based on 100 mol % of the base material main ingredient.

A dielectric ceramic composition includes a base material main component of barium titanate and a subcomponent. A microstructure of the dielectric ceramic composition after sintering includes a first grain having a Ca content of less than 3.5 at % and a second grain having a Ca content of 3.5 to 13.5 at %, and an area ratio of the second grain to an area of the total grains is 70% to 95%.

Provided is a dielectric composition exhibiting a high specific dielectric constant and a high resistivity even when fired in a reducing atmosphere. The dielectric composition contains a composite oxide having a composition represented by (Sr.sub.xBa.sub.1-x).sub.yNb.sub.2O.sub.5+y, the crystal system of the composite oxide is tetragonal, and y in the composition formula is smaller than 1.