A piezoelectric device including: a substrate having a cavity; a piezoelectric film covering the cavity and laminated and supported on the substrate; and a first electrode and a second electrode being provided to be spaced apart from each other so as to sandwich a part of the piezoelectric film. The first electrode and the second electrode pass through the piezoelectric film in the thickness direction of the piezoelectric film and are disposed above the cavity, an input signal is converted to an output signal based on displacement in a direction of application of a voltage to the piezoelectric film polarized in the direction of application of the voltage by applying the voltage between the first electrode and the second electrode, and a miniature piezoelectric device with high sensitivity is provided that utilizes the longitudinal effect of the piezoelectric effect.

A piezoelectric element includes a first electrode formed on a substrate, a piezoelectric layer formed on the first electrode and composed of a complex oxide having a perovskite structure containing potassium (K), sodium (Na), niobium (Nb), and manganese (Mn), and a second electrode formed on the piezoelectric layer. The manganese includes divalent manganese (Mn.sup.2+), trivalent manganese (Mn.sup.3+), and tetravalent manganese (Mn.sup.4+), a molar ratio of the divalent manganese to a sum of the trivalent manganese and the tetravalent manganese ((Mn.sup.2+/(Mn.sup.3++Mn.sup.4+)) is 1 or more and 10 or less, and a molar ratio of the potassium to the sodium (K/Na) is 1.1 or less.

A piezoelectric thin film is formed by adding a donor element to lead zirconate titanate. In the piezoelectric thin film, a molar ratio of lead to a total sum of zirconium and titanium is 105% or higher, and, when positive and negative coercive electric fields in polarization and electric field hysteresis are referred to as Ec (+) and Ec (?), respectively, a value of |Ec (+)|/|Ec (?)| is 0.5 or more and 1.5 or less.

A piezoelectric film includes a plurality of laminated main baking unit PZT layers. A first seed layer is present at a lower surface side of a lowermost main baking unit PZT layer. A second seed layer is interposed between two adjacent main baking unit PZT layers at an intermediate position between the lowermost main baking unit PZT layer and an uppermost main baking unit PZT layer.

Methods and systems are provided for a single element ultrasound transducer. In one embodiment, the ultrasound transducer comprises a front face, a back face parallel to the front face, a piezoelectric layer having a top surface electrically coupled to the signal pad and a bottom surface electrically coupled to the ground pad. In this way, the transducer can work robustly and may be automatically mounted to an imaging probe.

Described herein is a method and structure for fabricating a self-sensing piezoelectric actuator. In a single device, the actuator may be formed which is capable of movement, along with a sensor that may provide a signal indicative of the speed and/or magnitude of the movement. The actuator may be fabricated on one wafer, and the sensor fabricated on a second wafer, and the two wafers bonded together to form the device. The device may be appropriate for vibration devices such as ultrasound tranducers and the like. The structure may be fabricated using well known semiconductor techniques such as depositions, etching and ion implantation.

A piezoelectric element includes a first electrode, a piezoelectric layer which is provided on the first electrode and which is formed of crystals of a composite oxide with a perovskite structure which is preferentially oriented in a plane, and a second electrode which is provided on the piezoelectric layer and which is formed of platinum which is preferentially oriented in a plane, in which, in the piezoelectric layer, plane intervals L.sub.1 of the crystals on the first electrode side are larger than plane intervals L.sub.2 of the crystals on the second electrode side.

A piezoelectric thin film-stacked body is provided. A piezoelectric thin film-stacked body has a first electrode layer, a first intermediate layer stacked on the first electrode layer, a second intermediate layer stacked on the first intermediate layer, and a piezoelectric thin film stacked on the second intermediate layer, the first intermediate layer includes K, Na, and Nb, the second intermediate layer is a layer causing stress in a compression direction in the piezoelectric thin film, and the piezoelectric thin film includes (K,Na)NbO.sub.3.

A piezoelectric thin film-stacked body is provided. A piezoelectric thin film-stacked body has a first electrode layer, a first oxide layer stacked on the first electrode layer, a second oxide layer stacked on the first oxide layer, and a piezoelectric thin film stacked on the second oxide layer, the electrical resistivity of the first oxide layer is higher than the electrical resistivity of the second oxide layer, the first oxide layer includes K, Na, and Nb, and the piezoelectric thin film includes (K,Na)NbO.sub.3.

A multi-layered film includes an electroconductive layer made of platinum (Pt), a seed layer including lanthanum (La), nickel (Ni), and oxygen (O), and a dielectric layer being preferentially oriented in a c-axis direction, which are at least sequentially disposed on a main surface of a substrate made of silicon.