# US 9,039,921 B2 · Freestanding films with electric field-enhanced piezoelectric coefficients

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,039,921 B2
- Document ID: US9039921B2
- Status: Granted
- Kind: B2
- Application number: 12/784,173
- Filed: 2010-05-20
- Published: 2010-09-09
- Granted: 2015-05-26
- Earliest claimed: 2005-03-29
- Assignees: Drexel University
- Applicants: Wei-Heng Shih; Hongyu Luo; Christian Martorano; Wan Y. Shih
- Inventors: Wei-Heng Shih; Hongyu Luo; Christian Martorano; Wan Y. Shih
- Web page: https://patentgrep.com/patent/US9039921B2

## CPC

- H10N 30/853: Ceramic compositions
- C04B 35/495: based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
- C04B 35/499: containing also titanates
- C04B 35/6264: {Mixing media, e.g. organic solvents}
- C04B 35/628: Coating the powders {or the macroscopic reinforcing agents}
- C04B 35/6281: {Alkaline earth metal oxides}
- C04B 35/62886: {by wet chemical techniques}
- C04B 35/63424: {Polyacrylates; Polymethacrylates}
- H10N 30/097: by sintering
- H10N 30/50: having a stacked or multilayer structure
- H10N 30/8548: {Lead-based oxides}
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3251: Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
- C04B 2235/441: Alkoxides, e.g. methoxide, tert-butoxide
- C04B 2235/449: Organic acids, e.g. EDTA, citrate, acetate, oxalate
- C04B 2235/6025: Tape casting, e.g. with a doctor blade
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE

## Abstract

A method to produce low-temperature sinterable powders which are then subsequently used to fabricate freestanding piezoelectric films with very large electric-field-enhanced piezoelectric response is provided. The −d31 coefficient for PMN-PT layers can be as high as 2000 pm/V, larger than that of commercial single crystalline PMN-PT bulk materials, at 10 kV/cm (or 20 V over the 20-micron film thickness). In contrast to single crystals, the polycrystalline freestanding films are easy to fabricate and can be made into any size. The films are also easily miniaturized. The method can be applied to nearly any piezoelectric material.

## Claims

### Claim 1

A polycrystalline ceramic freestanding film having −d31 of from 1500 pm/V to 2000 pm/V at either 9 or 10 kV/cm, wherein the film has a thickness of a few grains up to 50 μm and said polycrystalline ceramic is either PMN-PT or PZN-PT.

### Claim 2 (depends on 1)

A polycrystalline ceramic freestanding film as claimed in claim 1, having a −d31 of at least 1800 pm/V at either 9 or 10 kV/cm.

### Claim 3 (depends on 1)

A polycrystalline ceramic freestanding film as claimed in claim 1, wherein the polycrystalline ceramic freestanding film is formed by reactive sintering of a calcined product which comprises lead magnesium niobate and a material reactive with the calcined product which comprises lead titanate.

### Claim 4 (depends on 1)

A device selected from the group consisting of sensors, actuators and microelectro-mechanical systems made using the polycrystalline freestanding film as claimed in claim 1.

### Claim 5 (depends on 4)

A device as claimed in claim 4, wherein the device is a microelectro-mechanical system.

### Claim 6

A polycrystalline ceramic freestanding film having −d31 of from 1500 pm/V to 2000 pm/V at either 9 or 10 kV/cm, wherein the film has a thickness of from 22 um to 50 μm and said polycrystalline ceramic is either PMN-PT or PZN-PT.

### Claim 7 (depends on 6)

A polycrystalline ceramic freestanding film as claimed in claim 6, having a −d31 of at least 1800 pm/V at either 9 or 10 kV/cm.

### Claim 8 (depends on 6)

A device selected from the group consisting of sensors, actuators and microelectro-mechanical systems made using the polycrystalline freestanding film as claimed in claim 6.

### Claim 9 (depends on 8)

A device as claimed in claim 8, wherein the device is a microelectro-mechanical system.