By Topic

Applications of Ferroelectrics, 1998. ISAF 98. Proceedings of the Eleventh IEEE International Symposium on

Date 24-27 Aug. 1998

Filter Results

Displaying Results 1 - 25 of 142
  • ISAF 1998. Proceedings of the Eleventh IEEE International Symposium on Applications of Ferroelectrics (Cat. No.98CH36245)

    Save to Project icon | Request Permissions | PDF file iconPDF (720 KB)  
    Freely Available from IEEE
  • Author index

    Page(s): 593 - 596
    Save to Project icon | Request Permissions | PDF file iconPDF (345 KB)  
    Freely Available from IEEE
  • Linear motor using hysteresis and resonance of piezoelectric element

    Page(s): 365 - 367
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    We developed a new type of piezoelectric linear motor harnessing a inertial force. The piezoelectric linear motor can be moved forward and backward by only a piece of the piezoelectric element. The linear motor consists of a bimorph piezoelectric element, trembler with a weight and a track. The difference of accelerations at a to-and-fro motion of the vibrating reed causes the linear motor to move. The resonance of the vibrating reed causes the linear motor to move in one direction View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dielectric property of BaTiO3-SrTiO3 artificially modulated structure made by MBE

    Page(s): 47 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    In order to elucidate the origin of the asymmetry observed in the D-E or C-V hysteresis loops of BaTiO3(BTO)-SrTiO3(STO) epitaxial films, “artificially modulated structures” (AMSs), where the chemical composition was continuously changed along the direction of film thickness, were prepared and their dielectric properties were measured. A fully automatic molecular beam epitaxy system was developed to fabricate AMSs. The simulation of XRD profiles indicated that a relaxation of the crystal lattice occurred along the a-axis in the two AMSs. It was observed that the asymmetry of the C-V hysteresis loop was changed by the modulation, and that the origin of the asymmetry was attributed to the lattice relaxation rather than the asymmetry of the stress field View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Degradation of perovskite Pb(Zr,Ti)O3 thin films fabricated by pulsed laser ablation

    Page(s): 23 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    Ferroelectric thin films of Pb(Zr,Ti)O3 (PZT) were prepared on platinum (Pt) and SrRuO3 (SRO) thin film electrodes by the fourth harmonic wave (λ=266 nm) of a pulsed Nd 3+:YAG laser ablation technique. Ferroelectric degradation of ferroelectric thin film capacitors is investigated. As a result, the remanent polarization value of PZT films deposited on an SRO electrode as a buffer layer remained constantly more than 1011 switching cycles. It is confirmed that polarization switching degradation is improved by using an SRO thin film electrode as a buffer layer View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The influence of strain on the dielectric behavior of (Bax Sr1-x)Ti1+yO3+z thin films grown by LS-MOCVD on Pt/SiO2/Si

    Page(s): 31 - 34
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    The strain state and its coupling to dielectric behavior have been investigated for {100} BST thin films deposited on Pt/SiO2/Si at 640°C. It is estimated from X-ray diffraction that the in-plane biaxial strain is approximately 0.7%. We postulate that this is of sufficient magnitude to confine any spontaneous polarization to the plane of the film. The thickness-corrected dielectric behavior perpendicular to the substrate for these samples shows evidence of coupling to such an in-plane phase transition at approximately 390 K, as manifested by deviation from Curie-Weiss-like behavior at this temperature View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Time dependence of mechanical depolarization in ferroelectric ceramics

    Page(s): 503 - 506
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    Piezoelectric PZT-ceramics exhibit the common feature that their piezoelectric response to electrical or mechanical stresses increases nonlinearly with the amplitude of the applied stress. This nonlinear increase is commonly interpreted in terms of domain wall motion. Thus for piezoelectric actuators based on this type of material the achieved displacement is not only due to the intrinsic piezoelectric effect, as observed in single domain crystals, but also to orientation processes of ferroelectric domains. While the quasistatic ferroelectric and ferroelastic properties of PZT are well known, there are only few published measurements concerning the dynamic behaviour of PZT-materials under large signal operation. In this paper a measurement method is presented, which allows the time dependence of mechanically induced domain processes to be studied. From such measurements, a comparison between the transient behaviour of various PZT compositions under different applied stresses is made. The transient force and charge responses from a stress-step is examined within the time range between 10 milliseconds and 60 seconds. Lastly it is also shown, that there is a fundamental difference in the transient response of donor-doped and acceptor-doped PZT ceramics View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ferroelectric and piezoelectric properties of lead-free (Bi1/2 Na1/2)TiO3-KNbO3-1/2(Bi2 O3·Sc2O3) ceramics

    Page(s): 559 - 562
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    Bismuth sodium titanate, (Bi1/2N1/2)TiO3 (BNT)-based solid solution, a(Bi1/2N1/2)TiO3-bKNbO3 -c1/2(Bi2O3·Sc2 O3) (a+b+c=1), [KTNS(100a/100b/100c)], was studied for its ferroelectric and piezoelectric properties, as a new group of lead-free piezoelectric ceramics. Piezoelectric measurements show that the KTNS ceramics near the BNT side have a relatively high electromechanical coupling factor, k33(=0.47). On particular, the amount of modified Bi3+ ions has an effect on k33 . These ceramics seem to be a candidate for lead-free piezoelectric ceramics View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dielectric properties of (Ba,Sr)TiO3 thin films deposited on Ni/TiN/Si substrate by photo-assisted metal organic chemical vapor deposition

    Page(s): 43 - 46
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB)  

    High dielectric strontium titanium oxide (STO) and barium strontium titanium oxide (BST) films have been deposited by photo-assisted metal organic chemical vapor deposition (PhAMOCVD) on Si(100) with Ni/TiN metallic buffer layers. The dielectric properties of capacitors based on the Ag/(Ba,Sr)TiO3/Ni/TiN/Si(100) heterostructure exhibited dielectric constants of from 300 to 600. Test structures of 3-D capacitors were fabricated using high permittivity MOCVD (Ba,Sr)TiO3 thin films deposited on the sidewalls of 3-D Ni/TiN electrodes patterned by reactive ion etching View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Processing and electromechanical properties of dome-shaped actuators fabricated by fused deposition of ceramics

    Page(s): 273 - 276
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (444 KB)  

    Dome-shaped actuators based on the soft PZT ceramics were successfully fabricated by Fused Deposition of Ceramics (FDC) which allows for 3D layer manufacturing of ceramic parts directly from a Computer-Aided Design (CAD) file. The curvature of the samples was varied in order to optimize the electromechanical response. The green structures obtained by FDC were subjected to a binder burnout cycle to remove the organic binder and were sintered at 1285°C for 1 hour. The electromechanical properties were then evaluated in terms of axial displacement, resonance behavior, and electromechanical hysteresis. Displacements of 7 μm were achieved from the samples with 23 mm and 1.4 mm in diameter and height, respectively. The results demonstrate that FDC technique can be used for rapid prototyping of monolithic actuators of complex shape while maintaining structural integrity and good piezoelectric properties View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ferroelectric ceramics with included porosity for hydrophone applications

    Page(s): 373 - 376
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    Porous piezoelectric ceramics have been prepared by mixing lead zirconate titanate (PZT) powder with fine particle organic additives. After mixing, the powder was cold pressed to form samples that were then heated to eliminate the organic component. Sintered samples were cut, polished, then electroded and poled in high electric field. Elastic, dielectric and piezoelectric characterisation was done on standard shape samples in agreement with IEEE standards. Important variations of those coefficients with respect to dense material were registered. In particular, the piezoelectric voltage coefficient was greatly increased. Moreover, with respect to starting dense PZT, the hydrostatic figure of merit for some compositions increased by almost two orders of magnitude, while the acoustical impedance was highly decreased. An optimum composition has been identified in order to obtain materials with high piezoelectric coefficients and reasonably good mechanical resistance and a set of samples was prepared for testing in a hydrophone device. Sensor elements with similar properties have been selected from this set and assembled in a planar hydrophone. Results on sensitivity measurements in air and under pressure are presented and discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Enhancement of memory window in the metal/ferroelectric (YMnO3 )/insulator/semiconductor capacitor

    Page(s): 39 - 42
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    We have investigated electrical properties of ferroelectric capacitors using Pt/YMnO3/Si and Pt/YMnO3/Y2 O3/Si structures. The YMnO3 thin film has c-axis oriented hexagonal structure after annealing at 900°C for 1 hr. C-V characteristics show that memory windows increase with the annealing temperature. Using Y2O3 films, we can reduce charge injection due to the electric field distribution between Y 2O3 and SiO2 View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Extension of an LVDT sensor system for thermal analysis for field-induced strain measurements of nonlinear ferroelectrics

    Page(s): 285 - 287
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (236 KB)  

    Increased demand for piezoelectric ceramics for actuators require application-orientated characterisation methods. For reasons of speed and cost it is of great advantage if existing measurement systems can be extended to include this option. Based on a LVDT (Linear Variable Differential Transformer) sensor system for thermal investigations, a sample holder for strain measurements with an applied electric field was developed. The sample holder can be used from -150°C to +400°C to determine the strain as a function of the applied electric field as well as the temperature. Using SF6 as an insulating gas, electric fields of several kV/mm can be applied. Specimens may be up to 12 mm in diameter and 50 mm in height. A confirmation of the flexibility of the measurement method is discussed in two examples. On the one hand, the influence of temperature on electrically induced strain of soft-doped PZT ceramics is shown. On the other hand, investigations of the electric fatigue behaviour of soft-doped PZT ceramics display constant or rising reversible strain with increasing numbers of cycles up to 105 cycles View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Nanometer control of the ferroelectric polarization in Pb(Zr0.2Ti0.8)O3 thin films

    Page(s): 431 - 434
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    Using scanning probe microscopy and atomically smooth epitaxial Pb(Zr0.2Ti0.8)O3 (PZT) thin films, we have investigated the possibility of controlling and modifying the ferroelectric polarization over large areas with submicron resolution. The films, which show a root-mean-square roughness of typically 2 A, could be uniformly polarized over areas as large as 2500 μm2 , and regular arrays of circular domains with a diameter of less than 100 nm, as well as lines with a width of 100 nm, could be written at arbitrary positions within the uniformly polarized areas. This local control of the polarization spans ten orders of magnitude in area and is ultimately limited by the sample size. We also report on studies of the intrinsic domain structure in films showing both c- and a-axis orientations. These films were characterized by transmission electron microscopy and X-ray diffraction. Local investigations of the ferroelectric properties were performed, and correlations between the microstructure and the ferroelectric properties are discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Properties of donor doped BaTi(Mn)O3+SiO2 sintered in reducing atmospheres

    Page(s): 525 - 528
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    Studies into the effect of trivalent (Ho, Nd, Y) and pentavalent (Nb, V) donor dopants on the material properties of BaTi(Mn)O3+SiO2 sintered under reducing conditions are presented. The effects of acceptor (Mn) concentration are also discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Growth of the 90°-domains in C-plates of NaNO2

    Page(s): 419 - 422
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    A sodium nitrite NaNO2 crystal is usually composed of 180° domains. These antiparallel ferroelectric domains are of (100) twin structure. The (121) twin structure which is well-known as the other twin is produced by the mechanical stress. Recently, it has been reported that (011) twin structure is produced by an application of a high ac electric field. The (011) twin in the matrix crystal is a rod shape region elongated to a-direction with a wedge type tip. The wall of the tip is moved by an additional application of an ac electric field and the rod grows toward the a-direction. The (011) twin is regarded as the ferroelectric 90°-domain of NaNO2. The growth of this new domain is reported in this paper View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Characterisation of piezoceramic under uniaxial stress

    Page(s): 307 - 310
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    An experimental set up has been developed for monitoring the static stress influence, up to 120 Mpa, on the dielectric ε33 piezoelectric and d33 mechanical s33 coefficients. For these coefficients, the same trends are always observed: an increase for moderate static stress followed by a decrease for higher stress. In a general manner, the soft material presents stronger variations, with a large hysteresis, than hard materials. By introducing dopants to block off the oxygen vacancies, the coefficients variations and the hysteresis loop are strongly reduced. A theoretical analysis leads to the different relationships between the variations of the considered coefficients versus the applied stress View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new characterization of piezoelectric thin films

    Page(s): 65 - 68
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    With the meditation for the measuring philosophy of normal loading method, piezoelectric properties of lead zirconate titanate thin film were investigated by pneumatic loading method, which is newly devised for more improved and reliable characterization technique. These results will be utilized to the piezoelectric micro-devices and give us more reliable expectation for the device performance and better understanding of piezoelectric thin film View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-resolution dry etch patterning of PZT for piezoelectric MEMS devices

    Page(s): 89 - 92
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    Dry etch patterning of lead zirconate titanate with self-aligned top and bottom platinum electrodes was demonstrated using a combination of reactive ion etching of PZT and argon ion milling of Pt. Monochlorotetrafluoroethane (HC2ClF4) etch gas and a Pt etch mask were employed for PZT patterning. PZT etch rates in the range 13-110 nm/min were measured as a function of rf discharge power for alumina, graphite, and ardel electrode shields in a conventional parallel plate reactor. The top and bottom platinum films were patterned by argon ion milling with a photoresist etch mask which was applied at the outset of the process and left in place throughout patterning. Etched profiles of Pt(200 nm)/PZT(500 nm)/Pt(150 nm) multilayer films were characterized by SEM and exhibited submicron definition View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Potentialities of 0.9PMN-0.1PT ceramics for active vibration control

    Page(s): 295 - 298
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    The potentialities of 0.1PMN-0.1PT ceramics for active vibration control were investigated. Consequently, the ceramic behavior as sensor and actuator were characterized. The dielectric and electromechanical responses have been measured, at room temperature for different compressive stresses, by applying a sinusoidal signal of variable amplitude and frequency in addition to a DC electric field (0.6 kV/mm). The resulting behavior is very well described in terms of hyperbolic tangent formulations which moreover allow to take into account the hysteresis of the curves View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effect of polarization distribution during heat flux modulation on the pyroelectric current frequency dependence

    Page(s): 191 - 194
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    The frequency dependence of the effective pyroelectric current, its real and imaginary components, and the phase shift between pyroelectric current and heat flux have been calculated from the given polarization distribution for the case of sinusoidal heat flux modulation. The calculations are compared with experiment for DTGS crystals. It is shown that the existence of a layer with inverse polarization has a considerable effect on the frequency dependence of the pyroelectric current effective value View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Li-containing ceramics with the TWB structure as new disordered ferroelectric materials

    Page(s): 499 - 502
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    Temperature-frequency dependences of dielectric permittivity for Li-containing ceramics of solid solutions BaxPb4-xLi2Nb10O30 with the tetragonal wolfram bronze (TWB) structure have been studied. The presence of ferroelectric-paraelectric phase transition and deep low-frequency dispersion of the dielectric permittivity have been established for all studied compounds. Possible mechanisms responsible for dielectric dispersion and their connection with disordered arrangement of Li cations have been discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fatigue characteristics of PZT capacitors with Ir/IrOx electrodes

    Page(s): 7 - 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    Fatigue characteristics of PZT capacitors with Ir/IrOx electrodes were investigated. The top and bottom Ir/IrOx electrodes prevented PZT capacitors from polarization fatigue up to 1011 cycles. This fact was explained by the assumption that the Ir/IrOx electrodes suppress the formation of two kinds of domain pinning sites at the PZT/electrode interfaces. These pinning sites would originate from oxygen vacancies. The PZT with Ti-rich composition would enhance the formation of the pinning sites View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Growth of new langasite single crystals for piezoelectric applications

    Page(s): 315 - 319
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    We have successfully grown La3Nb0.5Ga5.5O14 and La3Ta0.5Ga5.5O14 piezoelectric single crystals of size and quality comparable to La3 Ga5SiO14, by the Czochralski technique. The piezoelectric and device properties of the crystals were investigated. A search for new langasite-type materials was also performed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dielectric and pyroelectric properties of thin film PZT

    Page(s): 217 - 220
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    Monolithic integration of thin film uncooled IR detectors requires processes compatible with Si devices and thermal isolation strategies. A metalorganic chemical vapor deposition (MOCVD) process has been developed to address these needs that uses β-diketonate and mixed β-diketonate-alkoxide precursors in a liquid delivery approach. Process space has been explored, and high quality tetragonal thin Pb(Zr,Ti)O3 (PZT) films with nominal Zr/Ti ratios of 20/80 were deposited on Si wafers with Pt electrodes at temperatures between 475 and 550°C. Following a post deposition anneal at 650°C, permittivities (ε) ranging from 450 to 635 have been observed, along with pyroelectric coefficients (p) from 10 to 25 nC/cm2K. Dielectric loss (tan δ) was approximately 0.015 to 0.025. These values translate to good voltage and signal-to-noise figures of merit (p/cε and p/c(ε tan δ)1/2, respectively) for thin film devices, where c=heat capacity per unit volume. Low thermal budget processing at T⩽500°C also produced a similar combination of properties which suggest that this process can be used as a back-end fabrication step after the read-out integrated circuits (ROICs) are fully functioning on a Si wafer View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.