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Title: Development of “fragility” in relaxor ferroelectrics

Relaxor ferroelectrics (RFs), a special class of the disordered crystals or ceramics, exhibit a pronounced slowdown of their dynamics upon cooling as glass-forming liquids, called the “Super-Arrhenius (SA)” relaxation. Despite great progress in glass-forming liquids, the “fragility” property of the SA relaxation in RFs remains unclear so far. By measuring the temperature-dependent dielectric relaxation in the typical relaxor Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-x%PbTiO{sub 3} (PMN − x%PT) with 0 ≤ x ≤ 20.0, we in-depth study the “fragility” properties of the SA relaxation in PMN − x%PT. Such fascinating issues as the mechanism of the “fragility” at an atomic scale, the roles of the systematic configurational entropy change and interaction among relaxing units (RUs, including polar nanoregions and free dipoles) and the relation between “fragility” and ferroelectric order are investigated. Our results show that both the “fragility” of the temperature-dependent SA relaxation and ferroelectric order in the PMN − x%PT systems investigated arise thermodynamically from the configurational-entropy loss due to the attractive interaction among RUs, and develops as a power law, possibly diverging at the finite critical temperature T{sub c}. A reasonable physical scenario, based on our “configurational-entropy-loss” theory and Nowick's “stress-induced-ordering” theory, was proposed.
Authors:
 [1] ;  [2] ;  [3] ; ; ;  [4] ;  [4] ;  [3] ;  [5] ;  [1]
  1. College of Physics and Electronic Engineering, Hainan Normal University, Haikou 571158 (China)
  2. (United States)
  3. (China)
  4. State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)
  5. Bioengineering Program and Mechanical Engineering and Mechanics Department, Lehigh University, 19 Memorial Drive West, Bethlehem, Pennsylvania 18015 (United States)
Publication Date:
OSTI Identifier:
22278121
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CERAMICS; CONCENTRATION RATIO; COOLING; CRITICAL TEMPERATURE; CRYSTALS; ENTROPY; FERROELECTRIC MATERIALS; GLASS; LEAD COMPOUNDS; LIQUIDS; MAGNESIUM COMPOUNDS; NIOBATES; RELAXATION; RELAXATION LOSSES; TEMPERATURE DEPENDENCE; TITANATES