Dielectric ceramic composition and electronic device

1. A dielectric ceramic composition comprising:

BaTiO 3 as a main component,

MgO: 0.50 to 3.0 moles,

MnO: 0.05 to 0.5 moles,

oxide (RE 1 2 O 3 ) of element selected from Sm, Eu, and Gd,

oxide (RE 2 2 O 3 ) of element selected from Th and Dy,

oxide (RE 3 2 O 3 ) of element selected from Y, Ho, Er, Yb, Tm and Lu,

BaZrO 3 : 0.20 to 1.0 moles, and

oxide of element selected from V, Ta, Mo, Nb, and W: 0.05 to 0.25 moles as subcomponents wherein

each subcomponent is calculated as a conversion of an oxide or composite oxide, with respect to 100 moles of the main component, and

contents of said RE 1 2 O 3 . RE 2 2 O 3 and RE 3 2 O 3 satisfy

RE 1 2 O 3 <RE 2 2 O 3 and

(RE 1 2 O 3 +RE 2 2 O 3 )≦RE 3 2 O 3 .

2. The dielectric ceramic composition as set forth in claim 1 wherein contents of RE 1 2 O 3 , RE 2 2 O 3 and RE 3 2 O 3 with respect to 100 moles of the main component satisfy the following:

0.30 moles≦(RE 1 2 O 3 +RE 2 2 O 3 +RE 3 2 O 3 )≦1.50 moles.

3. The dielectric ceramic composition as set forth in claim 1 , further comprising 0.40 to 2.0 moles of sintering aid as a subcomponent with respect to 100 moles of the main component.

4. The dielectric ceramic composition as set forth in claim 1 wherein

RE 1 is Gd,

RE 2 is Dy, and

RE 3 is Y.

5. The dielectric ceramic composition as set forth in claim 1 wherein Ba/Ti, a mole ratio of Ba and Ti in BaTiO 3 , is 0.997 to 1.003.

6. The dielectric ceramic composition as set forth in claim 1 wherein c/a, a ratio of lattice constant of c-axis and the same of a-axis in crystal lattice of BaTiO 3 , is 1.0095 or more.

7. An electronic device having a dielectric layer made from dielectric ceramic composition as set forth in claim 1 and internal electrode layers.

8. A dielectric ceramic composition comprising:

BaTiO 3 as a main component,

MgO: 0.50 to 2.50 moles,

MnO: 0.05 to 0.35 moles,

RE 4 2 O 3 , RE 4 being rare earth element excluding Gd: 0.40 to 1.50 moles,

Gd 2 O 3 : 0.03 to 0.10 moles, excluding 0.10 moles,

BaZrO 3 : 0.20 to 0.70 moles, and

oxide of element selected from V, Ta, Mo, Nb, and W: 0.02 to 0.15 moles as subcomponents,

wherein each subcomponent is calculated as a conversion of an oxide or composite oxide, with respect to 100 moles of the main component.

9. The dielectric ceramic composition as set forth in claim 8 wherein RE 4 is at least one element selected from Y, Ho, Dy, Er and Yb.

10. The dielectric ceramic composition as set forth in claim 8 , further comprising 0.40 to 1.50 moles of sintering aid as a subcomponent with respect to 100 moles of the main component.

11. The dielectric ceramic composition as set forth in claim 10 wherein said sintering aid is at least one selected from oxides of Si, B and Li.

12. The dielectric ceramic composition as set forth in claim 8 wherein Ba/Ti, a mole ratio of Ba and Ti in BaTiO 3 , is 0.997 to 1.003.

13. The dielectric ceramic composition as set forth in claim 8 wherein c/a, a ratio of lattice constant of c-axis and the same of a-axis in crystal lattice of BaTiO 3 , is 1.0095 or more.

14. An electronic device having a dielectric layer made from dielectric ceramic composition as set forth in claim 8 and internal electrode layers.