Ivailo M. Pandiev; Mariya P. Aleksandrova
Abstract
In this paper, we propose interface electronic circuit for thin film piezoelectric sensing structures. An interface electronic prototype based on dynamically programmed Field Programmable Analog Array (FPAA) is configured to implement Root-Mean-Square (RMS) to DC (RMS-to-DC) conversion process, based ...
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In this paper, we propose interface electronic circuit for thin film piezoelectric sensing structures. An interface electronic prototype based on dynamically programmed Field Programmable Analog Array (FPAA) is configured to implement Root-Mean-Square (RMS) to DC (RMS-to-DC) conversion process, based on direct method. The studied piezoelectric sensors are prepared by conventional microfabrication technology, involving new lead-free piezoelectric polymer-oxide composite, consisting of gallium doped zinc oxide and polyvinylidene fluoride. The devices show sensitivity to low frequency, weak mechanical loads and exhibit excellent stability at multiple vibrational cycles. It was found that a mass load of 80 g causes DC voltage of 111.8 mV with instability of less than 10 mV, which is sufficient for detection purposes.
P. Kumari; R. Rai; A. L. Kholkin; A. Tiwari
Abstract
The ferroelectric Ca doped (Ba0.9575La0.04X0.0025) (Ti0.815Mn0.0025Nb0.0025Zr0.18)0.99O3 was prepared by a high-temperature solid state reaction technique. For the understanding of the electrical and dielectric property, the relation between the crystal structures, electrical transition and ferroelectric ...
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The ferroelectric Ca doped (Ba0.9575La0.04X0.0025) (Ti0.815Mn0.0025Nb0.0025Zr0.18)0.99O3 was prepared by a high-temperature solid state reaction technique. For the understanding of the electrical and dielectric property, the relation between the crystal structures, electrical transition and ferroelectric transitions with increasing temperature ( –160 to 35°C) have been analyzed. X- ray diffraction analysis of the powders suggests the formation of a single-phase material with monoclinic structure. Capacitance and tanδ of the specimens were measured in the temperature range from -160 to 35°Cat frequencies 1 kHz – 1 MHz. Detailed studies of dielectric and electrical properties indicate that the Curie temperature shifted to higher temperature with the increase in frequency. Moreover, the dielectric maxima dropped down rapidly initially and the dielectric peaks became extremely broad. The AC conductivity increases with increase in frequency. The low value of activation energy obtained for the ceramic samples could be attributed to the influence of electronic contribution to the conductivity.
S. Bhagat; K. Amar Nath; K.P. Chandra; R.K. Singh; A.R. Kulkarni; K. Prasad
Abstract
Lead-free pseudo-binary compounds (1-x)Ba(Fe1/2Nb1/2)O3–xBaTiO3; (0 ≤ x ≤ 1) have been synthesized at 1200°C using conventional ceramic technique and characterized by X-ray diffraction, scanning electron microscopy, dielectric and vibration sample magnetometer studies. The crystal structure ...
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Lead-free pseudo-binary compounds (1-x)Ba(Fe1/2Nb1/2)O3–xBaTiO3; (0 ≤ x ≤ 1) have been synthesized at 1200°C using conventional ceramic technique and characterized by X-ray diffraction, scanning electron microscopy, dielectric and vibration sample magnetometer studies. The crystal structure of the compounds is found to be monoclinic with the space group P2/m except for BaTiO3 for which it is tetragonal (P4/mmm). The incorporation of BaTiO3 significantly reduces the dielectric loss and improve the frequency and temperature stability of the dielectric properties of Ba(Fe1/2Nb1/2)O3. Compound 0.25Ba(Fe1/2Nb1/2)O3-0.75BaTiO3 exhibited a low value of temperature coefficient of capacitance (< ±3%) in the working temperature range (up to +85°C), room temperature dielectric constant equal to 282 and low loss tangent (~10-2) which meets the specifications for “Z5D” of Class II dielectrics of Electronic Industries Association. Hence, this composition might be a suitable candidate for capacitor applications. Besides, magnetic studies indicated the possibility of magneto-electric coupling in the system.
Jeewan Kumar; S. N. Choudhary; K. Prasad; R. N. P. Choudhary
Abstract
The polycrystalline sample of 0.25Ba(Bi1/2Ta1/2)O3-0.75BaTiO3 was synthesized using conventional solid state reaction technique. XRD analysis indicated the formation of a single-phase orthorhombic structure. The SEM analysis shows the grain sizes to be 0.12 to mm. Complex electric modulus analyses suggested ...
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The polycrystalline sample of 0.25Ba(Bi1/2Ta1/2)O3-0.75BaTiO3 was synthesized using conventional solid state reaction technique. XRD analysis indicated the formation of a single-phase orthorhombic structure. The SEM analysis shows the grain sizes to be 0.12 to mm. Complex electric modulus analyses suggested the dielectric relaxation to be of non-Debye type. Dielectric studies indicated the relaxor behavior of 0.25Ba(Bi1/2Ta1/2)O3-0.75BaTiO3. The correlated barrier hopping model was employed to explain the mechanism of charge transport in the system. The ac conductivity is found to obey the Jonscher’s power law. The nature of variation of dc conductivity with temperature suggested NTCR behavior with activation energy 0.36eV. The studied material can be a potential candidate for capacitor applications.
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