Abstract: A piezoelectric thin film contains a metal oxide having a perovskite structure. The metal oxide contains bismuth, potassium, titanium, magnesium, iron, and an element M. The element M is at least one element selected from the group consisting of gallium and cobalt. At least a part of the metal oxide is at least one crystal selected from the group consisting of a tetragonal crystal and an orthorhombic crystal. A (001) plane of the crystal is oriented in a normal direction of a surface of the piezoelectric thin film.

Abstract: Provided is a piezoelectric thin film containing a tetragonal crystal 1 of a perovskite type oxide and a tetragonal crystal 2 of the oxide. A (001) plane of the tetragonal crystal 1 and a (001) plane of the tetragonal crystal 2 are oriented in a normal direction of a surface of the piezoelectric thin film. An interval of the (001) plane of the crystal 1 is c1. An interval of a (100) plane of the crystal 1 is a1. An interval of the (001) plane of the crystal 2 is c2. An interval of a (100) plane of the crystal 2 is a2. c2/a2 is more than c1/a1. A peak intensity of diffracted X-rays of the (001) plane of the crystal 1 is I1. A peak intensity of diffracted X-rays of the (001) plane of the crystal 2 is I2. I2/(I1+I2) is from 0.50 to 0.90.

Abstract: Provided is a piezoelectric thin film containing a tetragonal crystal 1 of a perovskite type oxide and a tetragonal crystal 2 of the oxide. A (001) plane of the tetragonal crystal 1 and a (001) plane of the tetragonal crystal 2 are oriented in a normal direction of a surface of the piezoelectric thin film. An interval of the (001) plane of the crystal 1 is c1. An interval of a (100) plane of the crystal 1 is al. An interval of the (001) plane of the crystal 2 is c2. An interval of a (100) plane of the crystal 2 is a2. c2/a2 is more than c1/a1. A peak intensity of diffracted X-rays of the (001) plane of the crystal 1 is I1. A peak intensity of diffracted X-rays of the (001) plane of the crystal 2 is I2. I2(I1+I2) is from 0.50 to 0.90.

Abstract: A piezoelectric thin film element contains an electrode layer (first electrode layer) and a piezoelectric thin film directly or indirectly stacked on the electrode layer. The piezoelectric thin film contains a tetragonal crystal 1 of a perovskite-type oxide and a tetragonal crystal 2 of a perovskite-type oxide. A (001) plane of the tetragonal crystal 1 is oriented in a normal direction of a surface of the electrode layer. A (001) plane of the tetragonal crystal 2 is inclined with respect to the (001) plane of the tetragonal crystal 1. A spacing of (001) planes of the tetragonal crystal 1 is c1. A spacing of (100) planes of the tetragonal crystal 1 is a1. A spacing of (001) planes of the tetragonal crystal 2 is c2. A spacing of (100) planes of the tetragonal crystal 2 is a2. c1/a1 is larger than c2/a2.

Abstract: A piezoelectric thin film contains a lower layer and a first piezoelectric layer stacked on the lower layer. The first piezoelectric layer contains a tetragonal crystal 1 of a perovskite-type oxide. A (001) plane of the tetragonal crystal 1 is oriented in a normal direction dn of a surface of the first piezoelectric layer. A spacing of (100) planes of the tetragonal crystal 1 is a1. A spacing of (100) planes of a crystal contained in the lower layer is aL. A lattice mismatch rate between the first piezoelectric layer and the lower layer is 100×(aL?a1)/a1. The lattice mismatch rate is 3.0 to 12.1%. A rocking curve of diffracted X-rays of the (001) plane of the tetragonal crystal 1 is measured in an out-of-plane direction of the surface of the first piezoelectric layer. A FWHM of the rocking curve is 1.9 to 5.5°.

Abstract: A piezoelectric thin film 3 contains a metal oxide, the metal oxide contains bismuth, potassium, titanium, iron and element M, the element M is at least one of magnesium and nickel, at least a part of the metal oxide is a crystal having a perovskite structure, and a (001) plane, a (110) plane or a (111) plane of the crystal is oriented in a normal direction dn of the surface of the piezoelectric thin film 3.

Abstract: A piezoelectric thin film includes a first piezoelectric layer and a second piezoelectric layer directly stacked on the first piezoelectric layer. The first piezoelectric layer contains a tetragonal crystal 1 of a perovskite-type oxide. The second piezoelectric layer contains a tetragonal crystal 2 of a perovskite-type oxide. A (001) plane of the tetragonal crystal 1 is oriented in a normal direction do of a surface of the piezoelectric thin film. A (001) plane of the tetragonal crystal 2 is oriented in the normal direction dn of the surface of the piezoelectric thin film. An interval of the (001) plane of the tetragonal crystal 1 is c1, an interval of a (100) plane of the tetragonal crystal 1 is a1, an interval of the (001) plane of the tetragonal crystal 2 is c2, an interval of a (100) plane of the tetragonal crystal 2 is a2, c2/a2 is more than c1/a1 and c1/a1 is from 1.015 to 1.050.

Abstract: Provided is a piezoelectric thin film containing a tetragonal crystal 1 of a perovskite type oxide and a tetragonal crystal 2 of the oxide. A (001) plane of the tetragonal crystal 1 and a (001) plane of the tetragonal crystal 2 are oriented in a normal direction of a surface of the piezoelectric thin film. An interval of the (001) plane of the crystal 1 is c1. An interval of a (100) plane of the crystal 1 is a1. An interval of the (001) plane of the crystal 2 is c2. An interval of a (100) plane of the crystal 2 is a2. c2/a2 is more than c1/a1. A peak intensity of diffracted X-rays of the (001) plane of the crystal 1 is I1. A peak intensity of diffracted X-rays of the (001) plane of the crystal 2 is I2. I2/(I1+I2) is from 0.50 to 0.90.

Abstract: A piezoelectric thin film 3 contains a metal oxide, the metal oxide contains bismuth, potassium, titanium, iron and element M, the element M is at least one of magnesium and nickel, at least a part of the metal oxide is a crystal having a perovskite structure, and a (001) plane, a (110) plane or a (111) plane of the crystal is oriented in a normal direction dn of the surface of the piezoelectric thin film 3.