Losses in ferroelectric materials

Abstract

Ferroelectric materials are the best dielectric and piezoelectric materials known today. Since the discovery of barium titanate in the 1940s, lead zirconate titanate ceramics in the 1950s and relaxor-PT single crystals (such as lead magnesium niobate-lead titanate and lead zinc niobate-lead titanate) in the 1980s and 1990s, perovskite ferroelectric materials have been the dominating piezoelectric materials for electromechanical devices, and are widely used in sensors, actuators and ultrasonic transducers. Energy losses (or energy dissipation) in ferroelectrics are one of the most critical issues for high power devices, such as therapeutic ultrasonic transducers, large displacement actuators, SONAR projectors, and high frequency medical imaging transducers. The losses of ferroelectric materials have three distinct types, i.e., elastic, piezoelectric and dielectric losses. People have been investigating the mechanisms of these losses and are trying hard to control and minimize them so as to reduce performance degradation in electromechanical devices. There are impressive progresses made in the past several decades on this topic, but some confusions still exist. Therefore, a systematic review to define related concepts and clear up confusions is urgently in need. With this objective in mind, we provide here a comprehensive review on the energy losses in ferroelectrics, including related mechanisms, characterization techniques and collections of published data on many ferroelectric materials to provide a useful resource for interested scientists and engineers to design electromechanical devices and to gain a global perspective on the complex physical phenomena involved. More importantly, based on the analysis of available information, we proposed a general theoretical model to describe the inherent relationships among elastic, dielectric, piezoelectric and mechanical losses. For multi-domain ferroelectric single crystals and ceramics, intrinsic and extrinsic energy loss mechanisms are discussed in terms of compositions, crystal structures, temperature, domain configurations, domain sizes and grain boundaries. The intrinsic and extrinsic contributions to the total energy dissipation are quantified. In domain engineered ferroelectric single crystals and ceramics, polarization rotations, domain wall motions and mechanical wave scatterings at grain boundaries are believed to control the mechanical quality factors of piezoelectric resonators. We show that a thorough understanding on the kinetic processes is critical in analyzing energy loss behavior and other time-dependent properties in ferroelectric materials. At the end of the review, existing challenges in the study and control of losses in ferroelectric materials are analyzed, and future perspective in resolving these issues is discussed.

Investigation of Electrical Properties & Mechanical Quality Factor of Piezoelectric Material (PZT-4A)

“…In 2014 an experimental investigation was carried out to harvest energy by using piezoelectric generator over wide range of frequency and optimal load resistance [11]. Mechanical quality factor helps in designing of a sensor and actuator and it is one of the most important parameter to determine the energy loss characteristic of piezoelectric material [12,13].The range of the mechanical quality factor (Q m ) varies from 3700 at 158 kHz frequency to 930 at 1.18 MHz frequency [14]. A study reported a new class of piezoelectric materials having high mechanical quality factor which vibrate at 1.7MHz and have a lot of applications as sensor and actuator [15].…”

Co-Precipitation Synthesis and Characterization of SrBi2Ta2O9 Ceramic

“…22, With the synthesis conditions described above, the grain sizes are found to be extremely small, and may give rise to resistive and capacitive grain boundaries. As improved elsewhere, 23,24 the dielectric loss appears to be a strong function of grain size. Thus, the decrease in loss can be understood from the fact that the lower conductivity of the fine-grained ceramics is due to the higher density of resistive grain boundaries.…”

Domain evolution with electric field and delineation of extrinsic contributions in (K, Na, Li)(Nb, Ta, Sb)O3 single crystal

“…c 44 of KNLNST cannot be measured for the lack of single domain sample. According to our precious work, c E 44 and c E 55 of single domain orthorhombic KNN-based crystal are 7.80 Â 10 10 and 1.90 Â 10 10 N/m 2 , respectively, more than 5 times larger than those of the Pbbased crystals with the same domain structure (c E 44 ¼ 1.28 Â 10 10 and c E 55 ¼ 0.32 Â 10 10 N/m 2 ). 25,26 So, we may conclude that in the tetragonal phase, c 44 of KNLNST should be much larger than that of the Pb-based crystals.…”

“…7,8 The extrinsic contribution plays a critical role in various functionalities, such as dielectric properties, piezoelectric activity, and energy loss behavior. 9,10 In addition, understanding the mechanism of domain wall motions is very helpful to get some insight into the nonlinearity, frequency dispersion, and aging of physical properties. 11 For the investigation of domain structures, single crystals are preferred over ceramics because dynamic process of domain evolution with E filed and temperature can be easily observed in single crystals.…”