Frequency Spectra of Fatigue of PZT and other Ferroelectric Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
Xiaofeng Du ◽  
I-Wei Chen
Keyword(s):  
Thin Films ◽  
Frequency Response ◽  
High Frequency ◽  
Fatigue Behavior ◽  
Ferroelectric Thin Films ◽  
Physical Models ◽  
Fatigue Properties ◽  
Frequency Spectra ◽  
Wall Movement ◽  
Measuring Frequency

ABSTRACTPolarization and polarization fatigue of PZT and other ferroelectric thin films have been studied via the frequency spectra of D-E hysteresis. The coercive field (Ec) of PZT thin films has been found strongly dependent on the measuring frequency, while a relatively flat frequency response is observed with SrBi2Nb2O9 thin films. The different fatigue behavior can be attributed to such a difference in the frequency response. Physical models have been suggested to for domain wall movement in PZT and SrBi2Nb2O9 thin films. Based on these observations, a methodology has been proposed to evaluate the high frequency and fatigue properties of ferroelectric thin films.

Ferroelectric Thin Films for Applications in High Frequency Range

2005 ◽  
Vol 316 (1) ◽  
pp. 7-12 ◽  
Author(s):  
A. Rousseau ◽  
M. Guilloux-Viry ◽  
V. Bouquet ◽  
A. Perrin ◽  
G. Tanné ◽  
...  
Keyword(s):  
Thin Films ◽  
High Frequency ◽  
Ferroelectric Thin Films ◽  
High Frequency Range ◽  
Frequency Range

RF Magnetron Sputtered Ba0.96Ca0.04Ti0.84Zr0.16O3 Thin Films for High Frequency Applications

2004 ◽  
Vol 833 ◽  
Author(s):  
Ali Mahmud ◽  
T. S. Kalkur ◽  
N. Cramer
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Constant ◽  
Substrate Temperature ◽  
High Frequency ◽  
Satellite Communications ◽  
Ferroelectric Thin Films ◽  
Paraelectric State ◽  
Deposited Films

ABSTRACTPerovskite ferroelectric thin films in the paraelectric state exhibit outstanding dielectric properties, even at high frequencies (>1 GHz). The tunable dielectric constant of ferroelectric thin films can be used to design frequency and phase agile components. High dielectric constant thin film ferroelectric materials in the paraelectric state have received enormous attention due to their feasibility in applications such as decoupling capacitors and tunable microwave capacitors; the latter application has been fueled by the recent explosion in wireless and satellite communications. This paper reportsBa0.96Ca 0.04Ti0.84Zr0.16O3 (BCTZ) thin films that were deposited on Pt electrodes using radio frequency magnetron sputtering at a low (450 °C) substrate temperature. Sputtered thin film BCTZ at low substrate temperature is compatible with conventional integrated circuit technology. The structural characterization of the deposited films was performed by x-ray diffraction. The electrical characterization of the films was achieved by capacitance-voltage, current-voltage, and S-parameter (via vector network analyzer) measurements. In addition, the effect of post annealing on the deposited films was investigated. A detailed understanding of both their processing and material properties is discussed for successful implementation in high frequency applications.

Direct measurement of mechanical properties of (Pb,La)TiO3 ferroelectric thin films using nanoindentation techniques

2001 ◽  
Vol 16 (4) ◽  
pp. 993-1002 ◽  
Author(s):  
M. Algueró ◽  
A. J. Bushby ◽  
M. J. Reece
Keyword(s):  
Thin Films ◽  
Plastic Deformation ◽  
Lead Titanate ◽  
Mechanical Response ◽  
High Spatial Resolution ◽  
Ferroelectric Thin Films ◽  
Intergranular Porosity ◽  
Major Mechanism ◽  
Wall Movement ◽  
Film Substrate

A procedure using nanoindentation with spherical tipped indenters is presented that allows separation of elastic, anelastic, and plastic contributions to the deformation of thin films. The procedure was demonstrated on a range of lanthanum-modified lead titanate (Pb,La)TiO3 (PTL) ferroelectric thin films. Indentation stiffness coefficients ranging from 110 to 147 GPa have been obtained depending on the microstructure and orientation of the PTL films. This coefficient was equivalent to (and so, can be directly compared with) Young's modulus of a nontextured, unpoled ceramic when films do not present preferred orientation. The trends of the anelastic contribution with the thickness, structure, microstructure, and stress level at the film/substrate interface of the films were consistent with it being produced by ferroelastic domain wall movement. Pore compaction was a major mechanism of plastic deformation for the PTL films. Grain size also affected plastic deformation, probably as a consequence of its correlation with intergranular porosity. The technique has a high spatial resolution (contact area < 10 μm2 for the results presented here), which allowed the mechanical homogeneity of the films to be studied and inhomogeneities to be identified from their mechanical response (elastic, anelastic, and plastic).

Imprint and Fatigue Properties of Chemical Solution Derived Pb1–-xLax(ZryTi1–y)1–x/4O3 Thin Films

1999 ◽  
Vol 14 (4) ◽  
pp. 1371-1377 ◽  
Author(s):  
Seung-Hyun Kim ◽  
Dong-Joo Kim ◽  
JoonGoo Hong ◽  
S. K. Streiffer ◽  
A. I. Kingon
Keyword(s):  
Thin Films ◽  
Oxygen Vacancies ◽  
Fatigue Behavior ◽  
Strong Dependence ◽  
Fatigue Properties ◽  
Electronic Charge ◽  
Film Electrode ◽  
Defect Sites ◽  
Electrode Interface ◽  
Plzt Thin Films

We have investigated the effect of oxygen vacancies on imprint and fatigue behavior of the PLZT thin films. It is found that the compensation of oxygen vacancies with various dopant concentrations and electrode structures is an important process parameter in determining the tendency to imprint and fatigue. In the case of PLZT thin films, the voltage shifts related to imprint are attributed to the trapping of electrons at ionic defect sites such as oxygen vacancies near the film/electrode interface, the magnitude of polarization, and concentration of defect-dipole complexes involving oxygen vacancies such as V′Pb–V••o. The strong dependence of fatigue rate on electrode material for PLZT thin films is due to the effect of the ferroelectric/electrode interaction on the pinning and/or unpinning rate involving the accumulation of oxygen vacancies near the film/electrode interface during fatigue cycling. By using RuO2 as the top and/or bottom electrode instead of Pt, improved fatigue properties are obtained compared to Pt/PLZT/Pt capacitors. This is because a reduced accumulation of oxygen vacancies near the interface by the oxide electrode such as RuO2 may reduce the electronic charge trapping and, consequently, lead to less domain wall pinning.

High frequency response of amorphous tantalum oxide thin films

2001 ◽  
Vol 24 (3) ◽  
pp. 526-533 ◽  
Author(s):  
Jin-Young Kim ◽  
A. Garg ◽  
E.J. Rymaszewski ◽  
Toh-Ming Lu
Keyword(s):  
Thin Films ◽  
Frequency Response ◽  
High Frequency ◽  
Tantalum Oxide ◽  
Oxide Thin Films ◽  
High Frequency Response

scholarly journals Pathological and physiological high-frequency oscillations in focal human epilepsy

2013 ◽  
Vol 110 (8) ◽  
pp. 1958-1964 ◽  
Author(s):  
Andrew Matsumoto ◽  
Benjamin H. Brinkmann ◽  
S. Matthew Stead ◽  
Joseph Matsumoto ◽  
Michal T. Kucewicz ◽  
...  
Keyword(s):  
High Frequency ◽  
Motor Task ◽  
High Amplitude ◽  
Spectral Amplitude ◽  
Support Vector ◽  
Frequency Spectra ◽  
Time Frequency ◽  
Human Epilepsy ◽  
High Frequency Oscillations ◽  
Measuring Frequency

High-frequency oscillations (HFO; gamma: 40–100 Hz, ripples: 100–200 Hz, and fast ripples: 250–500 Hz) have been widely studied in health and disease. These phenomena may serve as biomarkers for epileptic brain; however, a means of differentiating between pathological and normal physiological HFO is essential. We categorized task-induced physiological HFO during periods of HFO induced by a visual or motor task by measuring frequency, duration, and spectral amplitude of each event in single trial time-frequency spectra and compared them to pathological HFO similarly measured. Pathological HFO had higher mean spectral amplitude, longer mean duration, and lower mean frequency than physiological-induced HFO. In individual patients, support vector machine analysis correctly classified pathological HFO with sensitivities ranging from 70–98% and specificities >90% in all but one patient. In this patient, infrequent high-amplitude HFO were observed in the motor cortex just before movement onset in the motor task. This finding raises the possibility that in epileptic brain physiological-induced gamma can assume higher spectral amplitudes similar to those seen in pathologic HFO. This method if automated and validated could provide a step towards differentiating physiological HFO from pathological HFO and improving localization of epileptogenic brain.

High‐frequency response of capacitors fabricated from fine grain BaTiO3 thin films

1995 ◽  
Vol 66 (26) ◽  
pp. 3683-3685 ◽  
Author(s):  
P. K. Singh ◽  
S. Cochrane ◽  
W.‐T. Liu ◽  
K. Chen ◽  
D. B. Knorr ◽  
...  
Keyword(s):  
Thin Films ◽  
Frequency Response ◽  
High Frequency ◽  
High Frequency Response ◽  
Fine Grain

Study of the High Frequency Dielectric Properties of SrBi2 Ta2O9 Ferroelectric Thin Films

2006 ◽  
Vol 514-516 ◽  
pp. 259-263 ◽  
Author(s):  
Nicola Delmonte ◽  
Bernard Enrico Watts ◽  
Fabrizio Leccabue ◽  
Paolo Cova ◽  
Giovanni Chiorboli
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Lead Zirconate Titanate ◽  
High Frequency ◽  
Equivalent Circuit Model ◽  
Microwave Dielectric Properties ◽  
Lead Zirconate ◽  
Ferroelectric Thin Films ◽  
Microwave Frequencies ◽  
Microwave Dielectric

In recent years several ferroelectric thin films have been studied at microwave frequencies; lead zirconate titanate (PZT) and barium-strontium titanate (BST) has been widely investigated. However, the microwave dielectric properties of strontium-bismuth tantalate (SBT) have not yet been investigated so widely [1]. The purpose of this work is the microwave characterization of the dielectric properties of an SBT thin film biased at different DC voltages. The dielectric properties of SBT make it a good material for the production of FERAM memories. Microwave characterizations may show other properties that could promote the SBT as good candidate for capacitors to be employed also in microwave circuits (e.g. resonators and filters). In this work a study of high frequency dielectric properties has been performed and equivalent circuit model has been used to correct the measurements.

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