Dielectric ceramic and laminated ceramic capacitor

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PROBLEM TO BE SOLVED : To provide dielectric porcelain which has high dielectric constant, excellent stability in the temperature characteristics of relative dielectric constant and small voltage dependency of insulation resistance and to provide a multilayer ceramic capacitor which has the dielectric porcelain as a dielectric layer and excellent life characteristics at a high temperature load test. SOLUTION : The dielectric porcelain contains barium titanate as a principal component, vanadium, magnesium, a rare earth element and manganese by predetermined ratios and consists mainly of a first crystal particle, which has ≥0.1 atom%/nm concentration slope of the rare earth element in a range from the surface of the first crystal particle to the depth of 15 nm, and a second crystal particle which has ≤0.05 atom%/nm concentration slope of the rare earth element in the same range from the surface of the second crystal particle to the depth of 15 nm. The average crystal particle size of the first crystal particles and that of the second crystal particles are 0.3-0.54 μm and 0.4-1 μm, respectively. Furthermore, the dielectric porcelain satisfies C2/(C1+C2)=0.3-0.7 (wherein C1 is the area ratio of the first crystal particle per unit area of the polished surface of the dielectric porcelain; C2 is that of the second crystal particle per unit area of the polished surface of the dielectric porcelain). COPYRIGHT : (C)2009, JPO&INPIT