权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Development of the Lead-free Relaxor Ferroelectrics and Giant Piezoelectric Materials, and Evaluation of the Physical Properties

无铅驰豫铁电体和巨压电材料的研制及物理性能评价

基本信息

批准号：
14340094
负责人：
SHIGEMATSU Hirotake
金额：
$ 6.66万
依托单位：
Shimane University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Development of new relaxor ferroelectric materials with lead-free compositions is an urgent problem in an environmental aspect. We have performed a research project to search for lead-free relaxor ferroelectric materials. (1)In the system of Ba-Ti oxides, we found a new ferroelectric material of BaTi_2O_5, that has a high Curie temperature Tc of 700-750 K and has a spontaneous polarization Ps of 7 μCcm^<-2> at room temperature (the crystal system is monoclinic, space group C_2). The crystal, prepared in air, has a sharp dielectric anomaly reaching ε'_b=30,000 at the ferroelectric Curie temperature of Tc=752 K and has a low dielectric loss even at high temperatures : tanδ<0.1 at 800 K. By contrast, the crystal prepared in a reducing atmosphere shows a diffuse phase transition near Tc=703 K. Thus the crystal is very desirable for high temperature application. Furthermore, we carried out X-ray diffraction measurement and Raman scattering measurement. XRD patterns of the pulverized single … More crystals were measured in the temperature range of 300-1000 K ; the thermal expansion coefficients of lattice-parameters were estimated. Tiny jumps were observed in the lattice constants vs.T curves around Tc by Δa/a=0.10%, Δb/b=-0.11% and Δc/c=0.13%. X-ray diffraction measurements for the single crystal were carried out at room temperature and at 773 K using a spherical sample. The result revealed atomic displacements responsible for the ferroelectricity of BaTi_2O_5. Up to now, no soft optic mode was observed by the Raman scattering measurements. Thus, we consider the mechanism of the ferroelectric phase transition of BaTi_2O_5 as the order-disorder type. (2)In the system of (Sr_<1-x>Ba_x)_2Nb_2O_7, we found a new ferroelectric phase at temperatures below 465 K for x=0.32. (3)In the system of K-Nb oxides, we found a new material K_5Nb_9O_<25>, which shows ferroelectric activity at temperatures below ca.100K. These new ferroelectric materials without lead ions, especially BaTi_2O_5, are promising for a variety of application such as condenser, electro-optic switch and FeRAM. Less

开发新型的无铅弛豫铁电材料是环境保护方面亟待解决的问题。我们进行了一个研究项目，寻找无铅弛豫铁电材料。(1)In在Ba-Ti氧化物体系中，发现了一种新的铁电材料BaTi_2O_5，它具有700-750 K的高居里温度Tc和7 μCcm ~ 2的室温自发极化率Ps<-2>（单斜晶系，空间群C_2）。在空气中制备的晶体在铁电居里温度Tc=752 K时具有明显的介电反常，达到B= 30，000，即使在高温下也具有低的介电损耗：在800 K时tanδ<0.1。相反，在还原气氛中制备的晶体在Tc=703 K附近显示扩散相变。因此，该晶体对于高温应用是非常理想的。此外，我们进行了X射线衍射测量和拉曼散射测量。粉末化的单组分的XRD图谱 ...更多信息在300-1000 K的温度范围内测量晶体的热膨胀系数的晶格参数进行了估计。在T_c附近，晶格常数随温度的变化曲线出现微小的跳跃，Δa/a= 0.10%，ΔB/B=-0.11%，Δc/c= 0.13%.在室温和773 K下使用球形样品进行单晶的X射线衍射测量。结果表明，BaTi_2O_5的铁电性是由原子位移引起的。到目前为止，通过拉曼散射测量没有观察到软光学模式。因此，我们认为BaTi_2O_5的铁电相变机制为有序-无序型。(2)In在（Sr_<1-x>Ba_x）_2Nb_2O_7体系中，当x=0.32时，在465 K以下发现了一个新的铁电相。(3)In在K-Nb氧化物体系中，发现了一种新材料K_5Nb_9O_2<25>，它在低于100 K的温度下表现出铁电活性。这些新型的无铅铁电材料，特别是BaTi_2O_5，在电容器、电光开关、铁电存储器等方面有着广阔的应用前景。少

项目成果

期刊论文数量（51）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Raman scattering study on ferroelectric (Ba0.32Sr0.68)2Nb2O7 ceramics

铁电(Ba0.32Sr0.68)2Nb2O7陶瓷的拉曼散射研究

DOI：
10.1016/j.mseb.2005.02.001
发表时间：
2005
期刊：
Materials Science and Engineering B-advanced Functional Solid-state Materials
影响因子：
3.6
作者：
A. Hushur;Y. Akishige;S. Kojima
通讯作者：
S. Kojima

N.Mori, S.Todo, Y.Akishige: "Metallization of Magnetite at High Pressures"Physica B. 312-313. 686-690 (2002)

N.Mori、S.Todo、Y.Akishige：“高压下磁铁矿的金属化”Physica B. 312-313。