Perovskite-type composite oxide powder

A perovskite-type composite oxide powder comprising:

• La;
• and
• at least one type of element selected from the group consisting of Sr, Ca, Co, Ni. Mn and Fe,
• wherein a BET specific surface area is less than 6.0 m2/g, and
• a formula (1) below is satisfied:
• 1
• ≤
• {
• (
• D
• 9
• ⁢
• 0
• ⁢
• B
• -
• D
• 1
• ⁢
• 0
• ⁢
• B
• )
• /
• D
• 5
• ⁢
• 0
• ⁢
• B
• }
• /
• {
• (
• D
• 90
• ⁢
• A
• -
• D
• 10
• ⁢
• A
• )
• /
• D
• 50
• ⁢
• A
• }
• ≤
• 2
• .
• 1
• (
• 1
• )
• in the formula,
• D10A is a cumulative 10% particle size (D10A) by volume, D50A is a cumulative 50% particle size (D50A) by volume and D90A is a cumulative 90% particle size (D90A) by volume when slurry containing a perovskite-type composite oxide powder obtained by adding 0.15 g of the perovskite-type composite oxide powder to 60 mL of 500 ppm sodium hexametaphosphate aqueous solution (dissolved in ion-exchange water) and dispersing a resulting mixture with an ultrasonic homogenizer at an ultrasonic output of 300 μA for 30 seconds is measured with a particle size distribution measuring device that uses a laser diffraction/scattering method, and
• D10B is a cumulative 10% particle size (D10B) by volume, D50B is a cumulative 50% particle size (D50B) by volume and D90B is a cumulative 90% particle size (D90B) by volume when slurry containing a perovskite-type composite oxide powder obtained by adding 0.15 g of the perovskite-type composite oxide powder to 60 mL of 500 ppm sodium hexametaphosphate aqueous solution (dissolved in ion-exchange water) is measured with a Microtrac particle size distribution measuring device.