	US 12,137,614 B2
	Piezoelectric composition, piezoelectric element, piezoelectric device, piezoelectric transformer, ultrasonic motor, ultrasonic wave-generating element, and filter element
Hiroki Katoh, Tokyo (JP); and Yumi Akiyama, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Appl. No. 17/430,972
Filed by TDK CORPORATION, Tokyo (JP)
PCT Filed Feb. 10, 2020, PCT No. PCT/JP2020/005142 § 371(c)(1), (2) Date Aug. 13, 2021, PCT Pub. No. WO2020/166562, PCT Pub. Date Aug. 20, 2020.
Claims priority of application No. 2019-024494 (JP), filed on Feb. 14, 2019.
Prior Publication US 2022/0140226 A1, May 5, 2022
Int. Cl. H10N 30/853 (2023.01); C04B 35/495 (2006.01); H02N 2/10 (2006.01); H03H 9/56 (2006.01); H10N 30/40 (2023.01); H10N 30/50 (2023.01)

CPC H10N 30/8542 (2023.02) [C04B 35/495 (2013.01); H02N 2/103 (2013.01); H03H 9/562 (2013.01); H10N 30/40 (2023.02); H10N 30/50 (2023.02); C04B 2235/3201 (2013.01); C04B 2235/3239 (2013.01); C04B 2235/3255 (2013.01); C04B 2235/3281 (2013.01)]

8 Claims

1. A piezoelectric composition containing:

at least one or more elements selected from the group consisting of lithium, sodium and potassium;

at least one or more elements selected from the group consisting of vanadium, niobium, and tantalum;

copper or copper and germanium; and

oxygen,

wherein the piezoelectric composition has a main phase, and a high Cu-concentration phase in which a content ratio of copper is higher than that in the main phase,

the main phase has a perovskite structure,

the high Cu-concentration phase has the perovskite structure or a structure similar to the perovskite structure,

O_gand Cu_gsatisfy relationships of 51≤O_g≤60 and 2.0≤Cu_g≤15, in which a content ratio of oxygen in the high Cu-concentration phase is set as O_g, and a content ratio of copper in the high Cu-concentration phase is set as Cu_g, and

a CV value of copper in the piezoelectric composition is 40 or more and 300 or less.