铅基弛豫铁电单晶的高性能化机理研究  

Exploration of the mechanisms enabling high performance in relaxor ferroelectric crystals

作　　者：李飞[1,2] Fei Li(Electronic Materials Research Labortary,Key Labortary of the Ministry of Education,School of Electronic Science and Engineering,Xi'an Jiaotong University,Xi'an710049,China;Siate Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an 710049,China)

机构地区：[1]西安交通大学电子科学与工程学院电子陶瓷与器件教育部重点实验室,西安710049 [2]西安交通大学金属材料强度国家重点实验室,西安710049

出　　处：《科学通报》2022年第32期3872-3881,共10页Chinese Science Bulletin

基　　金：国家自然科学基金(51922083)资助。

摘　　要：弛豫铁电单晶具有优异的介电、压电、电光以及热释电性能,是电子科学技术领域重要的功能电介质材料,我国在医疗超声诊断、水声换能器、精密驱动、电光调制等领域对其有重大需求.自20世纪90年代至今,弛豫铁电单晶一直是铁电压电材料领域的研究重点,为诸多压电器件,尤其是为医疗超声探头和水声换能器的性能提升带来了一次重大机遇.本文简要介绍弛豫铁电单晶的发展历史,并着重讨论本课题组近些年在弛豫铁电单晶高压电效应的起源、单晶铁电畴结构调控、单晶性能优化提升、新型弛豫铁电单晶器件开发方面的研究进展.Relaxor ferroelectric single crystals,exhibiting excellent dielectric,piezoelectric,electro-optic,and pyroelectric properties,are important functional dielectric materials in electronic technology.Since the 1990s,relaxor ferroelectric crystals have attracted considerable attention in the ferroelectric and piezoelectric research fields and improved the performance of numerous piezoelectric devices,especially medical ultrasonic imaging transducers.In this paper,we briefly introduce the history of relaxor ferroelectric crystals and then focus on the research progress of our group in recent years,as listed below.(1)To elucidate the contribution of polar nanoregions(PNRs)to piezoelectricity,we performed closely integrated experimental and computational studies on relaxor ferroelectric crystals.In this work,we obtained key experimental evidence(low-temperature dielectric relaxation)for the contribution of PNRs to the piezoelectric activity in relaxorPbTiO3(PT)crystals via cryogenic measurements,and more importantly,for the first time,we quantified the contribution of PNRs accounting for 50%–80%of the room-temperature dielectric and piezoelectric properties.Based on the phasefield simulations,we proposed a mesoscale mechanism wherein the PNRs are aligned in a ferroelectric matrix facilitating the polarization rotation,which successfully explains the contribution of PNRs to dielectric/piezoelectric properties.This work opens up a new material design paradigm that introduces local heterogeneities to achieve enhanced macroscopic responses.(2)Based on the origin of high piezoelectric activity in relaxor ferroelectric crystals,we proposed a theoretical approach,i.e.,judiciously introducing local structure heterogeneity,to engineer the interfacial energies,thereby increasing the piezoelectricity of ferroelectric materials.According to this method,we designed and fabricated a series of rare earth element-doped relaxor ferroelectric crystals with piezoelectric coefficients d33in the 3400–4100 pC/N,double the values of the u

关 键 词：弛豫铁电单晶 压电效应 铁电畴 压电器件 

分 类 号：TB34[一般工业技术—材料科学与工程]