摘要
Ca_(3)Ti_(2)O_(7)因其独特的铁电性来源和室温下优异的铁电性,成为目前最受关注的杂化非本征铁电体。本研究采用溶胶-凝胶法结合高温烧结制备了Ca_(3)Ti_(2)O_(7)陶瓷,研究了退火工艺(温度、时间和气氛)对其微结构、介电性和铁电性的影响。研究结果表明:氮气气氛、850℃下对Ca_(3)Ti_(2)O_(7)陶瓷退火30 min可获得较为优异的铁电性;相对于未退火的Ca_(3)Ti_(2)O_(7)陶瓷,退火后陶瓷的TiO_(6)八面体的面外倾侧角有一定程度增加;不同气氛下的退火处理会产生氧空位,从而使Ca_(3)Ti_(2)O_(7)陶瓷的晶粒尺寸有一定程度增大;真空退火后的陶瓷具有相对较大的晶粒尺寸和较多的氧空位,使其表现出相对较高的介电常数;经过退火处理的Ca_(3)Ti_(2)O_(7)陶瓷的漏电流均高于未退火的样品;通过对Ca_(3)Ti_(2)O_(7)陶瓷在不同气氛下进行退火处理可显著提升其剩余极化强度,同时矫顽场强有一定程度增加,其中空气和真空气氛下退火样品的剩余极化强度为2.9~3μC/cm^(2),表现出优异的杂化非本征铁电性。
Ca_(3)Ti_(2)O_(7)has become one of the most concerned hybrid improper ferroelectrics due to its unique origin of ferroelectricity and excellent ferroelectricity at room temperature.Ca_(3)Ti_(2)O_(7)ceramics were prepared by sol-gel method combined with high temperature sintering.The effects of annealing processes(temperature,dwelling time,and atmosphere)on the microstructure,dielectric,and ferroelectric properties were studied.The results show that compared with the unannealed Ca_(3)Ti_(2)O_(7)ceramics,the annealing at different atmospheres(air,nitrogen,and vacuum)leads to the increased out-of-plane tilt angle of TiO_(6) octahedron to a certain extent and increases oxygen vacancies in Ca_(3)Ti_(2)O_(7)ceramics.The increased oxygen vacancies result in its increased grain size of Ca_(3)Ti_(2)O_(7)ceramics to a certain extent.The sample annealed in vacuum has relatively large grain size and more oxygen vacancies,thereby leading to its relatively high dielectric constant.The leakage current of annealed Ca_(3)Ti_(2)O_(7)ceramics is higher than that of the unannealed sample.The remnant polarization and coercive field of Ca_(3)Ti_(2)O_(7)ceramics can be increased via annealing in different atmospheres.The remnant polarization of the samples annealed in air and vacuum atmosphere is 2.9-3μC/cm^(2),exhibiting superior hybrid improper ferroelectricity.
作者
王钥涵
陈大凯
周创
蔡苇
高荣礼
翟梦玉
张凤圆
WANG Yaohan;CHEN Dakai;ZHOU Chuang;CAI Wei;GAO Rongli;ZHAI Mengyu;ZHANG Fengyuan(Fengmingshan High School,Chongqing 400037,China;School of Metallurgy and Materials Engineering,Chongqing University of Science and Technology,Chongqing 401331,China;Chongqing Key Laboratory of Nano/Micro Composite Materials and Device,Chongqing 401331,China)
出处
《材料科学与工程学报》
CAS
CSCD
北大核心
2023年第6期958-967,共10页
Journal of Materials Science and Engineering
基金
重庆市高校创新研究群体资助项目(CXQT19031)
重庆市自然科学基金面上资助项目(cstc2020jcyj-msxmX0030)
重庆市中小学创新人才培养工程计划资助项目(CY211001)。
