Preparation of Functionally Graded PZT Ceramics Using Tape Casting

Navarro, A.; Whatmore, R. W.; Alcock, Jeffrey R.

doi:10.1007/s10832-004-5134-7

Cited by 24 publications

(18 citation statements)

References 4 publications

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“…The sample geometry will, therefore, have a large effect on the pyroelectric properties of a device. The influence of material grain size in pyroelectricity has been observed, 8,9 although macroscopic size effects are not as well studied and yet can have significant impact on the fundamental functional behavior of small-scale pyroelectric devices.…”

Section: Introductionmentioning

confidence: 99%

Small-scale piezoelectric devices: Pyroelectric contributions to the piezoelectric response

Wooldridge

Blackburn

McCartney

et al. 2010

Journal of Applied Physics

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The recent trend in miniaturization of piezoelectrically active devices is driving research on size effects of these functional materials under reduced length scales. In this paper, we measure and model the generation of charge in thin piezoelectric structures under sinusoidal hydrostatic pressure and show how the subsequent thermally induced pyroelectric effect dominates the response in the smallest samples. We calculate the temperature profiles through the lead zirconate titanate structures, and determine the pyroelectric coefficient in these materials to be p′=0.28±0.02 mC m−2 K−1. The analysis of the piezoelectric and pyroelectric charge response described in this paper has significant impact on the design and fundamental functional behavior of small-scale piezoelectric devices.

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Section: Introductionmentioning

confidence: 99%

Small-scale piezoelectric devices: Pyroelectric contributions to the piezoelectric response

Wooldridge

Blackburn

McCartney

et al. 2010

Journal of Applied Physics

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“…The piezoelectric coefficients, d 33,f and e 31,f , of a PZT thin film of 700 nm thick with 3 -5% porosity are about À 30¨À 25 pC/N and 1 C/m 2 , respectively, while those of a dense PZT thin film of 700 nm thick are about À 50 pC/N and 2 -3 C/m 2 , respectively. Introduction of pores into the PZT films with controllable porosity makes it possible to examine the concept [10,17] that the porous PZT films can actually have a higher pyroelectric figure of merit through lowering the permittivity. To compare the electrical properties of porous thin films to those of dense thin films, three samples, all 700 nm thick, were prepared with various single-layer thicknesses.…”

Section: Resultsmentioning

confidence: 99%

“…The reduction in pyrocoefficient in the film with porosity was in agreement with the observation in Refs. [10,17]. It should be noticed that PZT140 has a higher pyrocoefficient than PZT70, indicating that increasing a single-layer thickness from 70 to 140 nm increases the pyrocoefficient.…”

Section: Intensity (Counts)mentioning

confidence: 99%

Effect of porosity on the ferroelectric properties of sol–gel prepared lead zirconate titanate thin films

et al. 2005

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“…An alternative technique to potentially improve the performance of pyroelectric materials is to structure them in an advantageous way. Navarro et al [20] have studied functionally-gradient materials in which a porous layer is included in the centre of a laminated stack. This reduces the average volume specific heat of the material while also reducing the thermal conductivity.…”

Section: Methodsmentioning

confidence: 99%

Pyroelectric IR sensor arrays for fall detection in the older population

2005

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Uncooled pyroelectric sensor arrays have been studied over many years for their uses in thermal imaging applications. These arrays will only detect changes in IR flux and so systems based upon them are very good at detecting movements of people in the scene without sensing the background, if they are used in staring mode. Relatively-low element count arrays (16 x 16) can be used for a variety of people sensing applications, including people counting (for safety applications), queue monitoring etc. With appropriate signal processing such systems can be also be used for the detection of particular events such as a person falling over. There is a considerable need for automatic fall detection amongst older people, but there are important limitations to some of the current and emerging technologies available for this. Simple sensors, such as 1 or 2 element pyroelectric infra-red sensors provide crude data that is difficult to interpret; the use of devices worn on the person, such as wrist communicator and motion detectors have potential, but are reliant on the person being able and willing to wear the device; video cameras may be seen as intrusive and require considerable human resources to monitor activity while machine-interpretation of camera images is complex and may be difficult in this application area. The use of a pyroelectric thermal array sensor was seen to have a number of potential benefits. The sensor is wall-mounted and does not require the user to wear a device. It enables detailed analysis of a subject's motion to be achieved locally, within the detector, using only a modest processor. This is possible due to the relative ease with which data from the sensor can be interpreted relative to the data generated by alternative sensors such as video devices. In addition to the cost-effectiveness of this solution, it was felt that the lack of detail in the low-level data, together with the elimination of the need to transmit data outside the detector, would help to avert feelings intrusiveness on the part of the end-user. The main benefits of this type of technology would be for older people who spend time alone in unsupervised environments. This would include people living alone in ordinary housing or in sheltered accommodation (apartment complexes for older people with local warden) and non-communal areas in residential/nursing home environments (e.g. bedrooms and ensuite bathrooms and toilets). This paper will review the development of the array, the pyroelectric ceramic material upon which it is based and the system capabilities. It will present results from the Framework 5 SIMBAD project, which used the system to monitor the movements of elderly people over a considerable period of time.

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Preparation of Functionally Graded PZT Ceramics Using Tape Casting

Cited by 24 publications

References 4 publications

Small-scale piezoelectric devices: Pyroelectric contributions to the piezoelectric response

Small-scale piezoelectric devices: Pyroelectric contributions to the piezoelectric response

Effect of porosity on the ferroelectric properties of sol–gel prepared lead zirconate titanate thin films

Pyroelectric IR sensor arrays for fall detection in the older population

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