Patent ID: 8771559

Claim:
A conductive sintered oxide which comprises: a conductive crystal phase having a perovskite structure represented by (RE 1-c Sr c )M d O 3 , in which RE is a group of elements consisting of Yb and/or Lu and at least one element selected from Group IIIA excluding Yb, Lu and La and M is a group of elements consisting of Al and at least one element Selected from Groups IVA, VA, VIA, VITA and VIII, a first insulating crystal phase represented by RE 2 O 3 , in which RE is as defined above, and a second insulating crystal phase represented by SrAl 2 O 4 , wherein the conductive crystal phase has a coefficient c which satisfies 0.18<c<0.50, the conductive crystal phase has a coefficient d satisfying 0.67≦d≦0.93, the coefficient d indicating a ratio between an amount of the element group (RE1-cSrc) constituting A sites and the amount of the element group M constituting B sites of the conductive crystal phase, and a content of a third insulating crystal phase represented by RE 4 Al 2 O 9 , the content of the third insulating crystal phase represented by RE 4 Al 2 O 9 not including zero, is smaller than the content of the first insulating crystal phase and is smaller than the content of the second insulating crystal phase.