A multilayer ceramic capacitor includes a ceramic body having a dielectric layer disposed between two internal electrodes. The dielectric layer includes a plurality of dielectric grains. A grain boundary between at least two dielectric grains of the plurality of dielectric grains has a ratio Si/Ni of a weight of Si to a weight of Ni in the grain boundary that is at least 1 and 6 or less.

A multi-layer ceramic capacitor includes: a first region including a polycrystal including, as a main component, crystal grains free from intragranular pores; a second region that includes a polycrystal including, as a main component, crystal grains including intragranular pores and includes a higher content of silicon than a content of silicon in the first region; a capacitance forming unit including ceramic layers laminated along a first direction, and internal electrodes disposed between the ceramic layers; and a protective portion including a cover that covers the capacitance forming unit and constitutes a main surface facing in the first direction, a side margin constituting a side surface facing in a second direction orthogonal to the first direction, and a ridge constituting a connection portion, the connection portion connecting the main surface and the side surface to each other. The ceramic layers include the first region. The ridge includes the second region.

A method of manufacturing a ceramic dielectric, including: heat-treating a barium precursor or a strontium precursor, a titanium precursor, and a donor element precursor to obtain a conducting or semiconducting oxide, preparing a mixture including the conducting or semiconducting oxide and a liquid-phase acceptor element precursor, and sintering the mixture to form a ceramic dielectric, wherein the ceramic dielectric includes a plurality of grains and a grain boundary between adjacent grains, and wherein the plurality of grains including an insulating oxide comprising an acceptor element derived from the acceptor element precursor.

A multilayer capacitor includes a body including an internal electrode alternately disposed with a dielectric layer; and an external electrode disposed on the body and connected to the internal electrode. The dielectric layer includes a plurality of grains and grain boundaries disposed between adjacent grains, and the grain boundaries include a plurality of graphene platelets.

A multilayer ceramic electronic component includes: a body part including dielectric layers and internal electrodes disposed to face each other with respective dielectric layers interposed therebetween; and external electrodes disposed on an outer surface of the body part and electrically connected to the internal electrodes. The dielectric layer includes grains including: a semiconductive or conductive grain core region containing a base material represented by ABO.sub.3, where A is at least one of Ba, Sr, and Ca, and B is at least one of Ti, Zr, and Hf, and a doping material including a rare earth element; and an insulating grain shell region enclosing the grain core region.

A multilayer capacitor includes a body including an internal electrode alternately disposed with a dielectric layer; and an external electrode disposed on the body and connected to the internal electrode. The dielectric layer includes a plurality of grains and grain boundaries disposed between adjacent grains, and the grain boundaries include a plurality of graphene platelets.

A composite structure including a conductor region that is configured from a first oxide, and an insulator region that is configured from a second oxide and that surrounds the conductor region, wherein the first oxide and the second oxide are in hetero structure with each other. A powder and a fired body each having such a composite structure are also preferable.

A multilayer electronic component includes: a body including first and second internal electrodes alternately disposed with respective dielectric layers interposed therebetween; and first and second external electrodes disposed on the body to be connected to the first and second internal electrodes, respectively, wherein each of the dielectric layers includes Ba.sub.mTiO.sub.3 and includes a plurality of grains and grain boundaries formed between adjacent grains, and a sum of contents of Si and Dy in the grain boundary is 10 to 15 parts by weight.

A multilayer electronic component includes a body including a dielectric layer and an internal electrode disposed alternately with the dielectric layer, and an external electrode disposed on the body. The internal electrode includes nickel (Ni) and yttrium (Y), and an average thickness of the internal electrode is 50 nm or more to 250 nm or less.

A multilayer capacitor includes: a body including dielectric layers and first and second internal electrodes alternately disposed with respective dielectric layers interposed therebetween; and first and second external electrodes disposed on the body to be connected to the first and second internal electrodes, respectively. The dielectric layer contains BaTiO.sub.3 as a main ingredient, and includes a plurality of grains and grain boundaries formed between adjacent grains, the grain boundary containing Si in an amount of 8.0 to 18.0 wt % and Al and Mg in a total content of 2.0 to 6.0 wt %.