東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Structure - property relations in le...

Juhas, Pavol.

Linked to FindBook

Google Book

Amazon

博客來

Structure - property relations in lead tungstate based perovskite relaxor ferroelectrics.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Structure - property relations in lead tungstate based perovskite relaxor ferroelectrics./
Author:	Juhas, Pavol.
Description:	157 p.
Notes:	Source: Dissertation Abstracts International, Volume: 64-06, Section: B, page: 2865.
Contained By:	Dissertation Abstracts International64-06B.
Subject:	Engineering, Materials Science. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3095895
ISBN:	0496435205

Structure - property relations in lead tungstate based perovskite relaxor ferroelectrics.
Juhas, Pavol.

Structure - property relations in lead tungstate based perovskite relaxor ferroelectrics. - 157 p.

Source: Dissertation Abstracts International, Volume: 64-06, Section: B, page: 2865.

Thesis (Ph.D.)--University of Pennsylvania, 2003.

The structure and dielectric properties of (1 - x)Pb(Sc 2/3W1/3)O3-(x)PbTiO3 (PSW-PT), (1 - x)Pb(Sc2/3W1/3)O 3-(x)PbZrO3 (PSW-PZ) and (1 - x)Pb(Sc1/2W1/4Ti1/4)O3-( x)Pb(Sc1/2Nb1/2)O3 (PSWT-PSN) ceramics have been investigated over a full substitution range. All compositions with x < 0.5 adopt a cubic perovskite structure; however, for x ≤ 0.25 the periodicity of the lattice is doubled due to a 1:1 ordered distribution of the B-site cations. The structural order in PSW can be described by a "random site model" with one cation site occupied by Sc3+ and the other by a random distribution of the remaining ions ( Sc3+1/3W6+2/3 ). This ordering is destabilized in solid solutions of PSW with PbZrO 3, but highly stabilized by PbTiO3, with a degree of order in excess of 95% for x ≤ 0.25 in (1 - x )PSW-(x)PT. The distinct effects of Zr and Ti on the B-site order are accompanied by remarkably different alterations in the dielectric response of the two solid solutions. Both systems are relaxor ferroelectrics, and for the substitution of PZ the temperature of permittivity maximum Tepsilon,max increases with x. However, Tepsilon,max decreases for additions of Ti up to x ≈ 0.25, even though PT has a much higher Curie temperature ( TC = 763 K) than PZ (503 K). Variations of T epsilon,max in the PSW-PT system could be also induced by altering the degree of order of a given composition; changes as high as 50°C were observed for x = 0.25. Strong effects of order were also observed in (0.25)PSWT-(0.75)PSN, where the introduction of partial order induced a relaxor to ferroelectric transition. To understand the relations between the atomic structure and dielectric properties, the effects of PT and PZ on the structure and ordering of PSW were studied using synchrotron x-ray and neutron diffraction. Rietveld refinement was carried out on the PSW-PT and PSW-PZ systems to determine their average long-range crystallographic structure, along with Pair Distribution Function (PDF) analysis to probe the local displacements of the atoms. For x < 0.25 the B-cations form a 1:1 ordered doubled perovskite structure (space group Fm3¯ m). (Abstract shortened by UMI.)

ISBN: 0496435205Subjects--Topical Terms:

1017759
Engineering, Materials Science.

Structure - property relations in lead tungstate based perovskite relaxor ferroelectrics.
LDR:03126nmm 2200289 4500 001 1843842
005 20051017073406.5
008 130614s2003 eng d
020 $a 0496435205
035 $a (UnM)AAI3095895
035 $a AAI3095895
040 $a UnM $c UnM
100 1 $a Juhas, Pavol. $3 1932058
245 1 0 $a Structure - property relations in lead tungstate based perovskite relaxor ferroelectrics.
300 $a 157 p.
500 $a Source: Dissertation Abstracts International, Volume: 64-06, Section: B, page: 2865.
500 $a Supervisor: Peter K. Davies.
502 $a Thesis (Ph.D.)--University of Pennsylvania, 2003.
520 $a The structure and dielectric properties of (1 - x)Pb(Sc 2/3W1/3)O3-(x)PbTiO3 (PSW-PT), (1 - x)Pb(Sc2/3W1/3)O 3-(x)PbZrO3 (PSW-PZ) and (1 - x)Pb(Sc1/2W1/4Ti1/4)O3-( x)Pb(Sc1/2Nb1/2)O3 (PSWT-PSN) ceramics have been investigated over a full substitution range. All compositions with x < 0.5 adopt a cubic perovskite structure; however, for x ≤ 0.25 the periodicity of the lattice is doubled due to a 1:1 ordered distribution of the B-site cations. The structural order in PSW can be described by a "random site model" with one cation site occupied by Sc3+ and the other by a random distribution of the remaining ions ( Sc3+1/3W6+2/3 ). This ordering is destabilized in solid solutions of PSW with PbZrO 3, but highly stabilized by PbTiO3, with a degree of order in excess of 95% for x ≤ 0.25 in (1 - x )PSW-(x)PT. The distinct effects of Zr and Ti on the B-site order are accompanied by remarkably different alterations in the dielectric response of the two solid solutions. Both systems are relaxor ferroelectrics, and for the substitution of PZ the temperature of permittivity maximum Tepsilon,max increases with x. However, Tepsilon,max decreases for additions of Ti up to x ≈ 0.25, even though PT has a much higher Curie temperature ( TC = 763 K) than PZ (503 K). Variations of T epsilon,max in the PSW-PT system could be also induced by altering the degree of order of a given composition; changes as high as 50°C were observed for x = 0.25. Strong effects of order were also observed in (0.25)PSWT-(0.75)PSN, where the introduction of partial order induced a relaxor to ferroelectric transition. To understand the relations between the atomic structure and dielectric properties, the effects of PT and PZ on the structure and ordering of PSW were studied using synchrotron x-ray and neutron diffraction. Rietveld refinement was carried out on the PSW-PT and PSW-PZ systems to determine their average long-range crystallographic structure, along with Pair Distribution Function (PDF) analysis to probe the local displacements of the atoms. For x < 0.25 the B-cations form a 1:1 ordered doubled perovskite structure (space group Fm3¯ m). (Abstract shortened by UMI.)
590 $a School code: 0175.
650 4 $a Engineering, Materials Science. $3 1017759
650 4 $a Chemistry, Inorganic. $3 517253
650 4 $a Chemistry, Physical. $3 560527
690 $a 0794
690 $a 0488
690 $a 0494
710 2 0 $a University of Pennsylvania. $3 1017401
773 0 $t Dissertation Abstracts International $g 64-06B.
790 1 0 $a Davies, Peter K., $e advisor
790 $a 0175
791 $a Ph.D.
792 $a 2003
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3095895