铁电压电综述文章

This article has been downloaded from IOPscience. Please scroll down to see the full text article. 1998 Rep. Prog. Phys. 61 1267 (http://iopscience.iop.org/0034-4885/61/9/002) View the table of contents for this issue, or go to the journal homepage for more
Ferroelectric, dielectric and piezoelectric properties
1269
1. Introduction Interest in ferroelectric properties, materials and devices has been considerable over the last 10 years. On one hand, this interest has been driven by the exciting possibility of using ferroelectric thin films for nonvolatile memory applications and new microelectromechanical systems (MEMS). On the other hand, problems associated with applications of ferroelectric materials, such as polarization fatigue, ageing and field and frequency dependence of the piezoelectric, elastic and dielectric properties, generated intensive research of the fundamental properties of ferroelectrics. For most, if not for all currently considered applications, the main interest is in polycrystalline (ceramic) ferroelectrics and thin films, which are easier to make and which offer a larger variety of easily achievable compositional modifications than single crystals. The disadvantage of polycrystalline ferroelectrics and films is that their properties are often controlled by contributions from domain-wall displacements and other so-called extrinsic contributions, which are responsible for most of the frequency and field dependence of the properties, and whose theoretical treatment presents a considerable challenge. In addition, geometry of thin films imposes boundary conditions which sometimes lead to very different properties of films with respect to bulk materials and which must be taken into account when modelling devices. This paper focuses on ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics and reviews recent advances in this field. The pyroelectric properties are discussed only in terms of effects of external fields on the pyroelectric response and coupling with the piezoelectric and elastic effects. In the first part dielectric, elastic, piezoelectric, electrostrictive and pyroelectric relationships are given in the tensor form and discussed in terms of the material symmetry. Coupling of temperature, elastic, dielectric, piezoelectric and pyroelectric variables is then introduced using the thermodynamic approach. This introductory discussion on the symmetry effects and variable coupling is thought to be important, especially for nonspecialists in the field who work with thin films. Films can be grown in many orientations and with different boundary conditions, both of which define film properties, so that understanding of symmetry effects and constraints imposed by variable coupling becomes essential. In the second part, the most important phenomena of ferroelectric materials (polarization, hysteresis, domain walls, phase transitions) are first introduced by giving basic definitions and using the thermodynamic Landau–Ginzburg–Devonshire (LGD) approach. The LGD approach is presented in some detail as it is the most powerful method to study the behaviour of ferroelectric materials and, in particular, effects of external fields on the properties. Results of LGD theory are used throughout the review. The ferroelectric (polarization reversal, hysteresis behaviour, polarization fatigue, ageing), dielectric and piezoelectric properties of ferroelectric ceramics and thin films are then discussed in more detail with the emphasis on the influence of domain-wall structure, domain-wall displacement, defects, microstructure, depletion and depolarization effects, and external electric and mechanical fields on the properties.
Received 10 February 1998, in final form 5 May 1998
Abstract Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics are reviewed with the aim of providing an insight into different processes which may affect the behaviour of ferroelectric devices, such as ferroelectric memories and microelectro-mechanical systems. Taking into consideration recent advances in this field, topics such as polarization switching, polarization fatigue, effects of defects, depletion layers, and depolarization fields on hysteresis loop behaviour, and contributions of domain-wall displacement to dielectric and piezoelectric properties are discussed. An introduction into dielectric, pyroelectric, piezoelectric and elastic properties of ferroelectric materials, symmetry considerations, coupling of electro-mechanical and thermal properties, and definitions of relevant ferroelectric phenomena are provided.
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Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics
Download details: IP Address: 117.32.153.176 The article was downloaded on 11/12/2011 at 09:16
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Rep. Prog. Phys. 61 (1998) 1267–1324. Printed in the UK
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PII: S0034-4885(98)90105-1
Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics
Dragan Damjanovic
Laboratory of Ceramics, Department of Materials Science, Swiss Federal Institute of Technology—EPFL, 1015 Lausanne, Switzerland
0034-4885/98/091267+58$59.50
c 1998 IOP Publishing Ltd
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1268
D Damjanovic
Contents
Page 1. Introduction 1269 2. Symmetry of materials and tensor properties 1270 2.1. Introduction 1270 2.2. Tensor definition of the dielectric, piezoelectric, elastic, pyroelectric and electrostrictive coefficients 1270 2.3. Matrix notation 1273 2.4. Symmetry of materials 1273 3. Coupling of thermal, electrical and mechanical properties 1276 3.1. Thermodynamic relations 1276 3.2. Piezoelectric constitutive equations and electromechanical coupling factors 1277 4. Ferroelectric properties 1279 4.1. Definitions 1279 4.2. Ferroelectric domains 1280 4.3. Poling of ferroelectrics 1282 4.4. Ferroelectric hysteresis loop and polarization switching 1283 4.5. Strain–electric field curve 1286 4.6. Domain-wall contribution to the properties of ferroelectric materials 1287 4.7. Thermodynamics of ferroelectrics 1288 4.8. Microscopic theories and crystal structure considerations 1293 5. Effects of defects, microstructure and external fields on the ferroelectric properties1294 5.1. Introduction 1294 5.2. Polarization switching (hysteresis loops). Depletion and depolarization effects1295 5.3. Ferroelectric (polarization) fatigue 1297 5.4. Effects of external fields on ferroelectric properties 1302 5.5. Grain-size effects 1305 5.6. Ageing and internal bias fields in ferroelectric materials 1307 5.7. Retention, endurance and imprint 1309 6. Piezoelectric properties of ferroelectric materials 1310 6.1. Introduction 1310 6.2. PZT solid solution and the morphotropic phase boundary 1310 6.3. ‘Soft’ and ‘hard’ PZT compositions. Effect of defects 1312 6.4. Extrinsic piezoelectric response 1313 7. Pyroelectric effect 1319 7.1. Effects of electric field bias 1319 7.2. Clamped and free pyroelectric coefficient 1319 Appendix 1320 References 1321