Conductive sintered oxide, thermistor element including the same, and temperature sensor including the same

A conductive sintered oxide which comprises:

• a first crystal phase having a composition represented by RE14Al2O9 and
• a second crystal phase having a perovskite structure represented by (RE21-cSLc)(AlxM1y)O3, in which
• RE1 is a first element group consisting of Yb and/or Lu and at least one element selected from Group IIIA elements excluding Yb, Lu and La,
• RE2 is a second element group consisting of at least one element selected from Group IIIA elements excluding La and including at least one of the elements constituting the first element group RE1,
• SL is an element group consisting of at least one of Sr, Ca and Mg and which includes Sr as a main element thereof in terms of molar proportion, and
• M1 is an element group consisting of at least one element selected from Groups IVA, VA, VIA, VIIA and VIII excluding Cr,
• the coefficient c of the second crystal phase is in the range of 0.18<c<0.50, and
• the coefficients x and y of the second crystal phase are in the range of 0.95≦x+y≦1.1;
• wherein the conductive sintered oxide has a B constant of less than 2,000 K, within a temperature range of from −40° C. to +600° C.