Electrically conductive oxide sintered compact, thermistor element employing the same, and temperature sensor employing the same

A sintered electroconductive oxide characterized in that

• the oxide has a first crystal phase having a composition represented by RE14Al2O9 and a second crystal phase having a perovskite structure represented by (RE21-aSra)MO3, and the factor a of the second crystal phase satisfies the following condition:
• 0.18<a<0.50,
• wherein RE1 represents a first element group consisting of at least one of Yb and Lu and at least one species selected from among group 3A elements excluding Yb, Lu, and La;
• RE2 represents a second element group which contains at least one species selected from among group 3A elements excluding La and which contains at least one species selected from the first element group RE1;
• and
• M represents an element group consisting of Al and at least one species selected from among group 4A, 5A, 6A, 7A, and 8 elements,
• wherein the sintered electroconductive oxide has a B constant of less than 2,000 K, within a temperature range of from −40° C. to +600° C.

A thermistor element having a part formed of a sintered electroconductive oxide characterized in that

• the oxide has a first crystal phase having a composition represented by RE14Al2O9 and a second crystal phase having a perovskite structure represented by (RE21-aSLa)MO3, and that the factor a of the second crystal phase satisfies the following condition:
• 0.18<a<0.50,
• wherein RE1represents a first element group consisting of at least one of Yb and Lu and at least one species selected from among group 3A elements excluding Yb, Lu, and La;
• RE2represents a second element group which contains at least one species selected from among group 3A elements excluding La and which contains at least one species selected from the first element group RE1;
• M1represents an element group consisting of at least one species selected from group 4A, 5A, 6A, 7A, and 8elements;
• and
• M represents an element group consisting of the element group M1and Al;
• and
• SL represents an element group consisting of Sr, Ca, and Mg, with at least Sr being included at a predominant proportion by mole.