| abstract |
Perovskite related compound of the present invention have layered structures in which perovskite units and A-rare earth structure units are alternately arranged. The reduced cell parameters a r -c r and α r -γ r and the reduced cell volume V r are within the following ranges: a r =6.05±0.6 Å, b r =8.26±0.8 Å, c r =9.10±0.9 Å, α r =103.4±10°, β r =90±10°, γ r =90±10°, and V r =442.37±67 Å 3 . At least one of the reduced cell parameters a r -c r can be m/n times as large as the aforementioned values, where m and n are independent natural numbers, the square roots of 2 or 3 or integral multiples thereof. Values of a r , b r and c r can be replaced with one another, or values of α r , β r and γ r can be replaced with one another. |