Researching | JAD Volume 11 Issue 2,2021

Dielectric properties of amorphous Bi–Ti–O thin films

R. Sun, W. Xu, and R. B. van Dover

We report the unexpectedly excellent dielectric properties of amorphous thin films with compositions in the Bi–Ti–O system. Films were deposited by RF magnetron reactive co-sputtering. In the composition range of 0.5 x Bi1−xTixOy exhibits excellent dielectric properties, with a high dielectric constant, 𝜀r∼ 53,

Journal of Advanced Dielectrics

Publication Date: Jan. 01, 1900
Vol. 11, Issue 2, 2150009 (2021)

Get PDF

View fulltext

Lead-free 0–3-type composites: From piezoelectric sensitivity to modified figures of merit

Ashura N. Isaeva, and Vitaly Yu. Topolov

Effective piezoelectric properties, electromechanical coupling factors (ECF) and figures of merit (FOM) are studied in lead-free 0–3-type composites based on novel ferroelectric 0.965(K0.48Na0.52)(Nb0.96Sb0.04)O3–0.035Bi0.5Na0.5Zr0.15Hf0.75O3 ceramic. Systems of prolate ceramic inclusions are surrounded by a large poly Effective piezoelectric properties, electromechanical coupling factors (ECF) and figures of merit (FOM) are studied in lead-free 0–3-type composites based on novel ferroelectric 0.965(

K_{0.48}

{Na}_{0.52})

(

{Nb}_{0.96}

{Sb}_{0.04})

O₃–0.035

{Bi}_{0.5}

{Na}_{0.5}

{Zr}_{0.15}

{Hf}_{0.75}

O₃ ceramic. Systems of prolate ceramic inclusions are surrounded by a large polymer matrix that can be either monolithic (in the 0–3 composite) or porous (in the 0–3–0 composite). Non-monotonic volume-fraction dependences of the effective piezoelectric coefficients

g_{3 j}^{*}

, ECF

k_{3 j}^{*}

, squared FOM

d_{3 j}^{*} g_{3 j}^{*}

and their modified analogs for stress-driven systems are analysed, and examples of the high longitudinal piezoelectric sensitivity (

g_{33}^{*}

>

100 mV ⋅m/N) are considered. A role of microgeometrical factors, that promote the large effective parameters and anisotropy of properties in the 0–3-type composites, is highlighted. New “aspect ratio — volume fraction” diagrams are first built to describe conditions for high piezoelectric sensitivity, large modified FOM and their anisotropy in the studied composites. These advanced materials can be of value for piezoelectric sensor, energy-harvesting and related applications.Effective piezoelectric properties, electromechanical coupling factors (ECF) and figures of merit (FOM) are studied in lead-free 0–3-type composites based on novel ferroelectric 0.965(

K_{0.48}

{Na}_{0.52})

(

{Nb}_{0.96}

{Sb}_{0.04})

O₃–0.035

{Bi}_{0.5}

{Na}_{0.5}

{Zr}_{0.15}

{Hf}_{0.75}

O₃ ceramic. Systems of prolate ceramic inclusions are surrounded by a large polymer matrix that can be either monolithic (in the 0–3 composite) or porous (in the 0–3–0 composite). Non-monotonic volume-fraction dependences of the effective piezoelectric coefficients

g_{3 j}^{*}

, ECF

k_{3 j}^{*}

, squared FOM

d_{3 j}^{*} g_{3 j}^{*}

and their modified analogs for stress-driven systems are analysed, and examples of the high longitudinal piezoelectric sensitivity (

g_{33}^{*}

>

100 mV ⋅m/N) are considered. A role of microgeometrical factors, that promote the large effective parameters and anisotropy of properties in the 0–3-type composites, is highlighted. New “aspect ratio — volume fraction” diagrams are first built to describe conditions for high piezoelectric sensitivity, large modified FOM and their anisotropy in the studied composites. These advanced materials can be of value for piezoelectric sensor, energy-harvesting and related applications..

Journal of Advanced Dielectrics

Publication Date: Jan. 01, 1900
Vol. 11, Issue 2, 2150010 (2021)

Get PDF

View fulltext

Dielectric spectroscopy and structural characterization of nano-filler-loaded epoxy resin

S. G. Thakor, V. A. Rana, H. P. Vankar, and T. R. Pandit

This work outlines the characterization of epoxy resin [Bisphenol A-(epichlorhydrin): epoxy] and hardener [N(3-dimethylaminopropyl)-1,3-propylenediamine] with various inorganic nano-fillers. Dielectric characterizations of epoxy, hardener, neat epoxy (epoxy + hardener) and nano-epoxy (nano-filler + neat epoxy) composit This work outlines the characterization of epoxy resin [Bisphenol A-(epichlorhydrin): epoxy] and hardener [

N

(3-dimethylaminopropyl)-1,3-propylenediamine] with various inorganic nano-fillers. Dielectric characterizations of epoxy, hardener, neat epoxy (epoxy + hardener) and nano-epoxy (nano-filler + neat epoxy) composites loaded with 1 wt.% of inorganic nano-fillers (SiO₂, Al₂O₃, TiO₂ and ZnO) were carried out using precision LCR meter, over the frequency range of 1 kHz–2 MHz at a constant temperature of 300.15 K. The structural information of nano-fillers, neat epoxy and nano-epoxy composites was understood by Fourier transform infrared spectroscopy and by XRD. Moreover, hardness and shear strength (shear punch) were also determined in order to gain additional information about the mechanical properties of epoxy composite. Influence of inorganic nano-fillers on the dielectric properties, structural chemistry and mechanical properties of neat epoxy composite is discussed thoroughly in this study.This work outlines the characterization of epoxy resin [Bisphenol A-(epichlorhydrin): epoxy] and hardener [

N

(3-dimethylaminopropyl)-1,3-propylenediamine] with various inorganic nano-fillers. Dielectric characterizations of epoxy, hardener, neat epoxy (epoxy + hardener) and nano-epoxy (nano-filler + neat epoxy) composites loaded with 1 wt.% of inorganic nano-fillers (SiO₂, Al₂O₃, TiO₂ and ZnO) were carried out using precision LCR meter, over the frequency range of 1 kHz–2 MHz at a constant temperature of 300.15 K. The structural information of nano-fillers, neat epoxy and nano-epoxy composites was understood by Fourier transform infrared spectroscopy and by XRD. Moreover, hardness and shear strength (shear punch) were also determined in order to gain additional information about the mechanical properties of epoxy composite. Influence of inorganic nano-fillers on the dielectric properties, structural chemistry and mechanical properties of neat epoxy composite is discussed thoroughly in this study..

Journal of Advanced Dielectrics

Publication Date: Jan. 01, 1900
Vol. 11, Issue 2, 2150011 (2021)

Get PDF

View fulltext

Improved ferroelectric and piezoelectric properties of (

{Na}_{0.5}

K_{0.5})

NbO₃ ceramics via sintering in low oxygen partial pressure atmosphere and adding LiF

Bing-Yu Li, Xiao-Ming Chen, Mei-Dan Liu, Zi-De Yu, Han-Li Lian, and Jian-Ping Zhou

Dense (Na0.5K0.5)NbO3 lead-free ceramics with the simple composition were prepared via sintering in low oxygen partial pressure (pO2, ∼10−12 atm) atmosphere and adding LiF. All the ceramics have pure orthorhombic structure. Compared to the LiF-added (Na0.5K0.5)NbO3 ceramics sintered in air and the low pO2-sintered pure Dense (

{Na}_{0.5}

K_{0.5})

NbO₃ lead-free ceramics with the simple composition were prepared via sintering in low oxygen partial pressure (pO₂,

\sim

10^{- 12}

atm) atmosphere and adding LiF. All the ceramics have pure orthorhombic structure. Compared to the LiF-added (

{Na}_{0.5}

K_{0.5})

NbO₃ ceramics sintered in air and the low pO₂-sintered pure (

{Na}_{0.5}

K_{0.5})

NbO₃ ceramics without LiF addition, the present ceramics exhibit improved piezoelectric and ferroelectric properties. The piezoelectric constant

d_{33}

is 125 pC/N, and the converse piezoelectric constant

d_{33}

* is 186 pm/V. The dielectric constant and dielectric loss of the ceramics at room temperature and 1 kHz are 451 and 0.03, respectively. Under the measured electric field of 70 kV/cm, the remanent polarization is 25.9

μ

C/cm² and the coercive field is 13.9 kV/cm. Furthermore, if the base metals such as Cu and Ni powders were mixed into the green pellets and sintered in the low pO₂ atmosphere, the base metals cannot be oxidized, suggesting possibility of using base metals as electrodes.Dense (

{Na}_{0.5}

K_{0.5})

NbO₃ lead-free ceramics with the simple composition were prepared via sintering in low oxygen partial pressure (pO₂,

\sim

10^{- 12}

atm) atmosphere and adding LiF. All the ceramics have pure orthorhombic structure. Compared to the LiF-added (

{Na}_{0.5}

K_{0.5})

NbO₃ ceramics sintered in air and the low pO₂-sintered pure (

{Na}_{0.5}

K_{0.5})

NbO₃ ceramics without LiF addition, the present ceramics exhibit improved piezoelectric and ferroelectric properties. The piezoelectric constant

d_{33}

is 125 pC/N, and the converse piezoelectric constant

d_{33}

* is 186 pm/V. The dielectric constant and dielectric loss of the ceramics at room temperature and 1 kHz are 451 and 0.03, respectively. Under the measured electric field of 70 kV/cm, the remanent polarization is 25.9

μ

C/cm² and the coercive field is 13.9 kV/cm. Furthermore, if the base metals such as Cu and Ni powders were mixed into the green pellets and sintered in the low pO₂ atmosphere, the base metals cannot be oxidized, suggesting possibility of using base metals as electrodes..

Journal of Advanced Dielectrics

Publication Date: Jan. 01, 1900
Vol. 11, Issue 2, 2150012 (2021)

Get PDF

View fulltext

Impedance and modulus studies of

{Na}_{0.9}

{Ba}_{0.1}

{Nb}_{0.9}

(

{Sn}_{0.5}

{Ti}_{0.5})_{0.1}

O₃ ceramic

A. Oueslati, and A. Aydi

Polycrystalline Na0.9Ba0.1Nb0.9(Sn0.5Ti0.5)0.1O3 is prepared by the solid-state reaction technique. The formation of single-phase material was confirmed by an X-ray diffraction study and it was found to be a tetragonal phase at room temperature. Nyquist plots (Z′′ versus Z′) show that the conductivity behavior is accur Polycrystalline

{Na}_{0.9}

{Ba}_{0.1}

{Nb}_{0.9}

(

{Sn}_{0.5}

{Ti}_{0.5})_{0.1}

O₃ is prepared by the solid-state reaction technique. The formation of single-phase material was confirmed by an X-ray diffraction study and it was found to be a tetragonal phase at room temperature. Nyquist plots (

Z^{''}

versus

Z^{'})

show that the conductivity behavior is accurately represented by an equivalent circuit model which consists of a parallel combination of bulk resistance and constant phase elements (CPE). The frequency dependence of the conductivity is interpreted in terms of Jonscher’s law. The conductivity

σ_{d c}

follows the Arrhenius relation. The modulus plots can be characterized by the empirical Kohlrausch–Williams–Watts (KWW),

φ (t)

= exp(

- (t

/

τ)^{β})

function and the value of the stretched exponent (

β)

is found to be almost independent of temperature. The near value of activation energies obtained from the analyses of modulus and conductivity data confirms that the transport is through an ion hopping mechanism dominated by the motion of the (

O^{2 -})

ions in the structure of the investigated material.Polycrystalline

{Na}_{0.9}

{Ba}_{0.1}

{Nb}_{0.9}

(

{Sn}_{0.5}

{Ti}_{0.5})_{0.1}

O₃ is prepared by the solid-state reaction technique. The formation of single-phase material was confirmed by an X-ray diffraction study and it was found to be a tetragonal phase at room temperature. Nyquist plots (

Z^{''}

versus

Z^{'})

show that the conductivity behavior is accurately represented by an equivalent circuit model which consists of a parallel combination of bulk resistance and constant phase elements (CPE). The frequency dependence of the conductivity is interpreted in terms of Jonscher’s law. The conductivity

σ_{d c}

follows the Arrhenius relation. The modulus plots can be characterized by the empirical Kohlrausch–Williams–Watts (KWW),

φ (t)

= exp(

- (t

/

τ)^{β})

function and the value of the stretched exponent (

β)

is found to be almost independent of temperature. The near value of activation energies obtained from the analyses of modulus and conductivity data confirms that the transport is through an ion hopping mechanism dominated by the motion of the (

O^{2 -})

ions in the structure of the investigated material..

Journal of Advanced Dielectrics

Publication Date: Jan. 01, 1900
Vol. 11, Issue 2, 2150013 (2021)

Get PDF

View fulltext

Influence of sintering behavior on the microstructure and electrical properties of BaTiO₃ lead-free ceramics from hydrothermal synthesized precursor nanoparticles

Do Viet On, Le Dai Vuong, Truong Van Chuong, Dao Anh Quang, Ho Van Tuyen, and Vo Thanh Tung

BaTiO3 nanoparticles were synthesized by hydrothermal method using amorphous phase TiO2 precursor as the Ti-source. The microstructure and phase structure were determined using XRD, SEM and Raman spectroscopy analysis results. The results showed that BaTiO3 nanoparticles have tetragonal structure, average size of about

Journal of Advanced Dielectrics

Publication Date: Jan. 01, 1900
Vol. 11, Issue 2, 2150014 (2021)

Get PDF

View fulltext