Browsing by Author "Whatmore, Roger W."

Browsing by Author "Whatmore, Roger W."

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  • Fabrication of lead zirconate titanate ceramics for pyroelectric applications 
    Navarro, A. (Cranfield University, 2001-10)
    The objective of this work was twofold, i.e. to develop an aqueous route for tape casting Lead Ziconate Titanate (PZT)ceramics for pyroelectric applications and to optimise the die-pressing route for reducing defect size ...
  • Flextensional ultrasonic motor using the contour mode of a square piezoelectric plate. 
    Leinvuo, Joni T.; Wilson, Stephen A.; Whatmore, Roger W. (IEEE Institute of Electrical and Electronics, 2004-08-01)
    This paper presents the design, fabrication, and characterization of a new type of standing wave piezoelectric ultrasonic motor. The motor uses a metallic flextensional amplifier, or cymbal, to convert the contour mode ...
  • Flextensional ultrasonic piezoelectric micro-motor. 
    Leinvuo, Joni T.; Wilson, Stephen A.; Whatmore, Roger W.; Cain, Markys G. (IEEE Institute of Electrical and Electronics, 2006-12-01)
    This paper presents the experimental design, construction, and operational characteristics of a new type of standing wave piezoelectric ultrasonic micro-motor. The motor uses a composite stator, consisting of a metallic ...
  • Giant electrocaloric effect in the thin film relaxor ferroelectric 0.9 PbMg1/3Nb2/3O3–0.1 PbTiO3 near room temperature. 
    Mischenkoa, A. S.; Zhang, Qi; Whatmore, Roger W.; Scott, J. F.; Mathurb, N. D. (American Institute of Physics, 2006-12)
    We have recently observed a giant electrocaloric effect (12 K in 25 V) in 350 nm sol-gel PbZr0.95Ti0.05O3 films near the ferroelectric Curie temperature of 242oC. Here we demonstrate a giant electrocaloric effect (5 K ...
  • Investigation of electrocaloric effect in PMN-PT relaxor thin films 
    Correia, T. M.; Young, J. S.; Whatmore, Roger W.; Scott, J. F.; Nathur, N. D.; Zhang, Qi (American Institute of Physics, 2009-12-31)
    Permittivity measurements of a 0.93PMN-0.07PT thin film show a broad maximum near 35 ºC, and an anomaly at the depolarizing temperature Td = 18 ºC on heating only, suggesting a dipolar glass-relaxor phase transition. No ...
  • Investigation of the electrocaloric effect in a PbMg2/3Nb1/3O3-PbTiO3 relaxor thin film 
    Correia, T. M.; Young, J. S.; Whatmore, Roger W.; Scott, J. F.; Mathur, N. D.; Zhang, Qi (American Institute of Physics, 2009-05)
    Permittivity measurements of a 0.93PMN-0.07PT thin film show a broad maximum near 35 °C, and an anomaly at the depolarizing temperature Td = 18 °C on heating only, suggesting a dipolar glass-relaxor phase transition. No ...
  • Kinetics of phase transformations in lead scandium tantalate thin films 
    Battat, J.; Huang, Zhaorong; Donohue, P. P.; Todd, M. A.; Whatmore, Roger W. (Taylor and Francis, 2004)
    The phase transformations from amorphous to pyrochlore to perovskite in lead scandium tantalate (PST) thin films during rapid thermal annealing process (RTA) have been studied. Volume fractions for pyrochlore and perovskite ...
  • Low fatigue lead zirconate titanate-based capacitors modified by manganese for nonvolatile memories 
    Zhang, Qi; Whatmore, Roger W. (Elsevier, 2004-06-15)
    We have investigated the effects of Mn doping on the ferroelectric properties of Pb(Zr0.3Ti0.7)O3 (PZT) thin films on substrates Pt/Ti/SiO2/Si. Small amount of Mn-doped (≤1 mol%) PZT (PMZT) showed almost no hysteretic ...
  • A model of phase transition kinetics in lead scandium tantalate thin films 
    Battat, J.; Huang, Zhaorong; Donohue, P. P.; Whatmore, Roger W. (Taylor and Francis, 2003)
    The phase transformations from amorphous to pyrochlore to perovskite in lead scandium tantalate (PST) thin films during rapid thermal annealing process (RTA) have been studied by X-ray diffraction (XRD) techniques. The ...
  • Modified bismuth titanate piezoelectric ceramics 
    Sanson, Alessandra (2003-12)
    Bismuth compounds are considered the most suitable alternatives to lead-based systems for ferroelectric and piezoelectric applications. Nevertheless little has been done to systematically study the relationships that ...
  • Nanostructured bottom electrodes for ferroelectric thin films 
    Wilson, R. (Cranfield University, 2001-09)
    Lead zirconate titanate (PZT) is a oxide, which posseses a perovskite type structure. The material is ferroelectric making it technically useful for a diverse range of applications from thermal imaging to non-volatile ...
  • A new flextensional piezoelectric ultrasonic motor - design, fabrication and characterisation 
    Leinvuo, Joni T.; Wilson, Stephen A.; Whatmore, Roger W.; Cain, Markys G. (Elsevier, 2007-01-08)
    This paper presents the techniques used for the characterisation of a new type of standing-wave piezoelectric ultrasonic motor. The motor uses a metallic flextensional amplifier, or “cymbal”, to convert the radial mode ...
  • Novel piezoelectric thick film actuators 
    Haigh, Richard (Cranfield University, 2005-03)
    Planar-spiral piezoelectric-unimorph-actuators, that deflect out-of-their-plane, were modelled, designed and fabricated. A range of other planar piezoelectric-device designs has also been made. These include spokes, ...
  • Porous, functionally gradient pyroelectric materials 
    Shaw, Christopher P.; Whatmore, Roger W.; Alcock, Jeffrey R. (Blackwell Publishing, 2007-01)
    Properties of a new type of pyroelectric ceramic structure containing a layer of known porosity laminated between two dense layers, to form a functionally gradient material (FGM), are reported. The combination of theoretical ...
  • PST thin films for electrocaloric coolers 
    Correia, T. M.; Kar-Narayan, S.; Young, J. S.; Scott, J. F.; Mathur, N. D.; Whatmore, Roger W.; Zhang, Qi (Iop Publishing Ltd, 2011-04-07)
    Relaxor behaviour in a thin film of partially ordered PbSc0.5Ta0.5O3 (PST) was confirmed via slim P-E loops and the frequency dependence of the temperature at which the dielectric constant is maximum. Indirect measurements ...
  • Pyroelectric arrays using ceramics and thin films integrated radiation collectors: design fabrication and testing 
    Whatmore, Roger W.; Landi, Spartaco; Shaw, Christopher P.; Kirby, Paul B. (Taylor and Francis, 2005-07)
    Pyroelectric infra-red detectors have been of-interest for many years because of their wide wavelength response, good sensitivity and lack of need for cooling. Arrays of such detectors, comprising a pyroelectric material ...
  • Pyroelectric ceramics and thin films for applications in uncooled infra-red sensor arrays 
    Whatmore, Roger W.; Zhang, Qi; Shaw, Christopher P.; Dorey, Robert A.; Alcock, Jeffrey R. (Royal Swedish Academy of Sciences, 2007-11-22)
    Pyroelectric infra-red detector arrays provide an attractive solution to the problem of collecting spatial information in the far IR. They are only sensitive to changes in the IR flux and are well suited to sensing ...
  • Reactive ion etching techniques for uncooled pyroelectric detectors 
    Landi, S (2005-03)
    This research presents the design and microfabrication of a novel pyroelectric IR array detector. Micromachined concentrators are incorporated in the device to focus incoming radiation. Patterning of the sensing elements ...
  • Sol-gel derived lead zirconate titanate thick films and their improved pyroelectric properties 
    Zhang, Qi; Shaw, Christopher P.; Huang, Zhaorong; Whatmore, Roger W. (Taylor and Francis, 2004)
    The single-layer thickness of Pb(Zr0.3Ti0.7)O3(PZT 30/70) thin films made by the sol-gel process is often restricted by the appearance of cracks when a single layer is thicker than 100 nm. Making a film with 1μm thick needs ...
  • Steps towards ceramic process scale-up: analysis of a laboratory process 
    Mortara, L.; Navarro, A.; Whatmore, Roger W.; Alcock, Jeffrey R. (Elsevier Science B.V., Amsterdam., 2004-01-01)
    In this paper the first steps towards a scaling up of a ceramic process are described, using as case study a lab-scale process, in which PZT ceramics are produced via an aqueous tape casting route. The process, the result ...