Spontaneous polarization and piezoelectric properties of AlN nanowires: Maximally localized Wannier functions analysis

Electroceramics are used in a variety of applications such as sensors, actuators, capacitors, and varistors. In these applications, the ceramic microstructure often consists of equiaxed, randomly oriented grains. Ferroelectric transducers require poling to obtain useful piezoelectric properties. Poling is difficult for some ferroelectric ceramics because the symmetry-related orientations available for the spontaneous polarization are limited.

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EFFECT OF YTTRIUM ON DIELECTRIC, PYROELECTRIC AND PIEZOELECTRIC PROPERTIES OF PBN FERROELECTRICS

International Journal of Modern Physics B ◽

10.1142/s0217979206035345 ◽

2006 ◽

Vol 20 (21) ◽

pp. 3081-3091 ◽

Cited By ~ 2

Author(s):

K. SAMBASIVA RAO ◽

N. VALLIS NATH ◽

P. MURALI KRISHNA ◽

D. MADHAVA PRASAD ◽

JOON HYUNG LEE

Keyword(s):

Transition Temperature ◽

Spontaneous Polarization ◽

Room Temperature ◽

Piezoelectric Properties ◽

Pyroelectric Coefficient ◽

Tetragonal Symmetry ◽

Maximum Volume ◽

Stiffness Constant ◽

Method Substitution ◽

Sintering Method

Materials with batch formula Pb (1-x-3y/2) R y Ba x Nb 2 O 6, where R=Y, (1-x)=0.73, 0.63, 0.53 and y=0.00, 0.02 have been prepared by the double sintering method. Substitution of yttrium (Y) restored tetragonal symmetry of PBN but reduced lattice parameters, cell volume and enhanced the density. Transition temperature of PBN has decreased due to the substitution of Y3+. Enhanced room temperature spontaneous polarization (Ps)=149.97 μ C/sq. cm has been observed in PBN53, which is above MPB, whereas enhanced value of Ps=112.74 μ C/sq. cm is found in Y: PBN63 at MPB region. The room temperature Pyroelectric coefficient (PRT=1.07) has been observed in the composition where maximum volume of Ps is obtained. Similarly, enhanced values of piezoelectric coefficients Kp=0.244, Kt=0.353, K31=0.131, d31=60, d33=159 and g31=3.65 have also been found in the same material PBN53. Substitution of Yttrium enhanced the stiffness constant 13.59 in PBN 73 to 14.27 of Y: PBN73.

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PLZT Microfibers Technology Optimization

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0241 ◽

2016 ◽

Vol 61 (3) ◽

pp. 1471-1476

Author(s):

L. Kozielski ◽

M. Adamczyk ◽

K. Feliksik ◽

D. Bochenek ◽

F. Clemens

Keyword(s):

Spontaneous Polarization ◽

Laser Excitation ◽

Piezoelectric Properties ◽

Sintering Temperature ◽

Waste Heat ◽

Pyroelectric Coefficient ◽

Ferroelectric Materials ◽

Quick Response ◽

New Generation ◽

Ferroelectric And Piezoelectric Properties

Abstract Electrocaloric (EC) structures for a new generation of cooling or heating elements utilize the temperature dependence of spontaneous polarization in some ferroelectric materials to convert waste heat into electricity and vice versa. A (Pb0.93La0.07) (Zr0.65Ti0.35)O3 material, have the largest recorded pyroelectric coefficient. An effective predicted form for such applications is fiber, due to small heat capacitance and quick response time, even for nano second laser excitation. Consequently, the presented work provides a description of the optimization of structural, ferroelectric and piezoelectric properties of obtained fibers, finally concluding on necessity of sintering temperature reduction in 100°C in contrast to bulk form to effectively prevent its destruction.

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