ELECTROMECHANICAL COEFFICIENTS OF MAGNETOELECTRIC PZT–CoFe2O4 COMPOSITE

2000 ◽  
Vol 14 (17n18) ◽  
pp. 663-674 ◽  
Author(s):  
K. SRINIVAS ◽  
G. PRASAD ◽  
T. BHIMASANKARAM ◽  
S. V. SURYANARAYANA

The magnetoelectric property of composite materials consisting of piezoelectric and piezomagnetic constituents are of interest since the stresses induced in them on application of an external magnetic field are converted into electrical signals. The electrical output is primarily due to electromagnetic coupling between the two participating phases. The present paper deals with the evaluation of the electromechanical coupling in the magnetoelectric composite consisting of 50% lead zirconate titanate (Pb0.96Sr0.04Ti0.47Zr0.53O3) and 50% CoFe2O4, the composition having maximum magnetoelectric conversion efficiency. A sum rule is proposed to calculate the electromechanical coupling coefficient and the results are correlated with the experimental data.

2011 ◽  
Vol 22 (16) ◽  
pp. 1879-1886 ◽  
Author(s):  
Clark Andrews ◽  
Yirong Lin ◽  
Haixiong Tang ◽  
Henry A. Sodano

Piezoelectric ceramics offer exceptional sensing and actuation properties, however, they are prone to breakage and are difficult to apply to curved surfaces in their monolithic form. One method to alleviate these issues is through the use of 0–3 active composites, which are formed by embedding piezoelectric particles into a polymer matrix that protects the ceramic from breaking under mechanical loading. This class of material offers certain advantages over monolithic materials; however, they have seen little use due to the low electromechanical coupling offered by these materials. Here, we demonstrate that by controlling the aspect ratio of the filler, the electromechanical coupling coefficient can be significantly improved. For all volume fractions tested, nanocomposites with high aspect ratio lead nanowires filler had higher coupling with increases as large as 2.3 times. Furthermore, the nanocomposite’s coupling was more than 50% of the piezoceramic fillers’ when nanowires were used.


2007 ◽  
Vol 345-346 ◽  
pp. 1521-1524 ◽  
Author(s):  
Mamoru Mizuno ◽  
Nozomi Odagiri ◽  
Mitsuhiro Okayasu

In the present paper, lead zirconate titanate (PZT) and lead titanate (PT) piezoelectric ceramics were subjected to both high electric field (which is higher than the coercive electric field) with low frequency and low electric field with high frequency (which is the resonance frequency). After applying certain electric field systematically, resonance and anti-resonance frequencies and an electrostatic capacity were measured by means of an impedance analyzer, and an electromechanical coupling coefficient, a dielectric constant, an elastic coefficient and a piezoelectric constant were evaluated from the frequencies and capacity measured. Then variation of the material properties in process of time was investigated experimentally, and the dependence of the variation of the properties due to mainly domain switching on conditions of applied electric field was elucidated.


2020 ◽  
Vol 225 ◽  
pp. 04012
Author(s):  
JY. Ferrandis ◽  
O. Gatsa ◽  
P. Combette ◽  
D. Fourmentel ◽  
C. Destouches ◽  
...  

In this article we present a first part of the results obtained during an irradiation campaign conducted at the Jozef Stefan Institute to observe the behaviour of piezoelectric materials under gamma and neutron flux. Specific instrumentation has been developed and has enabled the monitoring throughout the irradiation of several materials such as lead zirconate titanate (PZT) or modified Bismuth Titanate (BiT) in either massive or thick film form. Various parameters such as resonance frequency, electromechanical coupling coefficient, electrical capacitance, dielectric losses were measured as a function of the flow and dose received. The results obtained confirm that the samples work up to doses of 10 18 n°/cm2 and that the behaviour of the samples varies according to their composition and form.


2011 ◽  
Vol 01 (01) ◽  
pp. 85-89 ◽  
Author(s):  
B. P. ZHU ◽  
Q. F. ZHOU ◽  
C. H. HU ◽  
K. K. SHUNG ◽  
E. P. GORZKOWSKI ◽  
...  

Novel PZT-5A ceramic-polymer composite was prepared via freezing technology. This composite exhibited good dielectric and ferroelectric behaviors. At 1 kHz, the dielectric constant and the dielectric loss were 546 and 0.046, respectively, while the remnant polarization was 13.0 μC/cm2 at room temperature. The electromechanical coupling coefficient (kt) of PZT-5A composite was measured to be 0.54, which is similar to that of PZT piezoelectric ceramic. The piezoelectric coefficient (d33) of PZT-5A composite was determined to be ~250 pC/N. Using this composite, a 58 MHz single element transducer with the bandwidth of 70% at –6dB was built, and the insertion loss was tested to be –29dB around the central frequency.


2019 ◽  
Vol 30 ◽  
pp. 07015
Author(s):  
Sergey Ivanov ◽  
Gennady Semenov ◽  
Denis Kovalenko

The results of the magnetoelectric effect study in the magnetopiezofiber are presented. Magnetopiezofiber consists of mechanically coupled piezoelectric (one layer of lead zirconate titanate) and magnetostrictive (two metglass layers) fibers. The layers were joined together by epoxy under pressure and heating. The sample active area dimensions were 28x7x0,34 mm. The study of the magnetoelectric effect was carried out in the frequency range from 0 to 150 kHz and external magnetic field range from 0 to 100 Oe. Maximum value of the ME voltage coefficient αE = 62,75 V/cm-Oe was measured on the electromechanical resonance frequency f = 61 kHz with an external magnetic field of 4,5 Oe. Obtained results indicate the prospects of the proposed design in magnetoelectric devices application.


2020 ◽  
Author(s):  
Wei Liu ◽  
lehui zhang ◽  
Yu Cao ◽  
Jianhong Wang ◽  
Peikang Bai ◽  
...  

Abstract In this study, 3-3 type cement-based piezoelectric composites were prepared by casting Portland cement paste in porous lead zirconate titanate (PZT) ceramics, then the Polyvinylidene fluoride (PVDF) of N-Methylpyrrolidone (NMP) solvent with concentration of 50-200 mg/ml was utilized to modify the PZT-PC composites. The influence of PVDF concentration on the density, microstructure, dielectric, piezoelectric and electromechanical properties were investigated. The results indicate that the density of PZT-PC composites increased gradually with PVDF concentration for the increasing combined weight of PVDF with the composites. The introduction of PVDF has also contributed to the reduction of leakage current during the poling and testing process, which led to increased relative permittivity εr and longitudinal piezoelectric strain coefficient d33, while the dielectric loss tanδ and longitudinal piezoelectric voltage coefficient g33 demonstrated an opposite changing trend. Both the thickness electromechanical coupling coefficient Kt and planar electromechanical coupling coefficient Kp of the PZT-PC composites increased with PVDF concentration. The acoustic impedance (Z) of PVDF modified PZT-PC composites ranged from 6.89 to 7.65 MRayls, making it suitable for applications in the health monitoring of civil engineering.


2000 ◽  
Vol 657 ◽  
Author(s):  
Jürgen Brünahl ◽  
Alex Grishin ◽  
Sergey Khartsev

ABSTRACTFerroelectric lead zirconate titanate (PZT) is the main industrial product in piezoelectric ceramic materials used for sensor and actuator applications. High precision in manufacturing of microelectromechanical systems is essential to get demanded performance accuracy. An adequate and preferably non-destructive measurement technique is desired to characterize the materials properties at various stages of device fabrication as well as to find correlation between the processing parameters, microstructure and functional properties. We report on a new pulsed technique, which has been employed to characterize all relevant properties of special machined array of PZT channels quickly, reliably and reproducibly: dielectric constant, loss factor tan σ, electromechanical coupling coefficient, resonance frequency and mechanical quality factor Q as well as temperature dependencies of these parameters.


Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 74
Author(s):  
Tsam Lung You ◽  
Hemma Philamore ◽  
Fumitoshi Matsuno

In this work we present a soft crawler fabricated using a magneto-active elastomer. The crawler is controlled by an external magnetic field to produce two locomotion patterns: peristaltic and caterpillar crawling. Due to its structural simplicity, low mass, wirelessly controlled actuation and compliant body the design of this crawler has the potential to address the key challenges faced by existing crawling robots. Experimental data were gathered to evaluate the performance of the crawler locomotion in a pipe. The results validated the mathematical models proposed to estimate the distance traveled by the crawler. The crawler shows potential for use in exploration of confined spaces.


2002 ◽  
Vol 748 ◽  
Author(s):  
C. L. Zhao ◽  
Z. H. Wang ◽  
W. Zhu ◽  
O. K. Tan ◽  
H. H. Hng

ABSTRACTLead zirconate titanate (PZT) films are promising for acoustic micro-devices applications because of their extremely high electromechanical coupling coefficients and excellent piezoelectric response. Thicker PZT films are crucial for these acoustic applications. A hybrid sol-gel technology has been developed as a new approach to realize simple and cost-effective fabrication of high quality PZT thick films. In this paper, PZT53/47 thick films with a thickness of 5–50 μm are successfully deposited on Pt-coated silicon wafer by using the hybrid sol-gel technology. The obtained PZT thick films are dense, crack-free, and have a nano-sized microstructure. The processing parameters of this technology have been evaluated. The microstructure of the film has been observed using field-emission scanning electron microscopy and the crystallization process has been monitored by the X-ray diffraction. The thick films thus made are good candidates for fabrication of piezoelectric diaphragm which will be an essential element of microspeaker and microphone arrays.


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