MECHANISM FOR APPEARANCE OF MULTIFUNCTIONAL OF FERROELECTRICS WITH GIANT SPONTANEOUS POLARIZATION AND DEVELOPMENT FOR MULTIFUNCTIONAL SENSOR FUSION

近年来，从铁电材料发展的根本利益和实际意义出发，对扩散相变(弛豫行为)的研究受到了极大的关注。本工作采用PbO-熔剂法生长了复合钙钛矿结构中B位化学有序度微观可控的弛豫基铁电单晶。研究了弛豫铁电体单晶和陶瓷的结构、光学、介电、热释电、压电性能，包括：Pb(Mg_&lt；1/3&gt；Nb_&lt；2/3&gt；)O_3(Pphn)，Pb(Zn_&lt；L/3&gt；Nb_&lt；2/3&gt；)O_3(Pzn)，Pb(In_&lt；L/2&gt；Nb_&lt；L/2&gt；)O_3(PIn)，Pb(In_2&gt；L/2&gt；Nb_&lt；L/2&gt；)O_3(PIn)，Pb(In_2&gt；)用X射线衍射、偏光显微镜、拉曼散射和阻抗…等方法研究了1/2和1/2)O_3(PMW)、Pb(Sc_&lt；1/2&gt；Ta1_&lt；1/2&gt；)O_3(Pst)及其固溶体与PbTiO_3(PT)和PbZrO_3(PZ)等铁电材料的组成、温度、压强和直流偏置电场的关系更多的增益相位分析仪。我们发现，体积效应(即超额体积伴随着B位的无序)在松弛行为的表现中起着重要作用。这种体积效应和化学效应是通过合适的B位取代效应来实现的。此外，在弛豫基铁电固溶体中，介电常数、介电常数和机电耦合等大的铁电性质是由弛豫铁电固溶体中同形相界附近的异相共存(如铁电、反铁电和松弛/介观微团簇/多个极化位置共存)引起的。从弛豫铁电体的这种共存，可以预期梯度功能铁电材料(例如，多功能传感器融合)的发展。特别是PIN-PT、PIN-PZ和PMW-PT固溶体体系具有优异的介电、热电和压电性能。较少

Recently much attention has been given to diffuse phase transition (relaxor behavior) from viewpoint of fundamental interest and also practical importance in the development of ferroelectric materials. In this work, some relaxor-based ferroelectric single crystals with microscopically controlled ordering degree of chemical ordering at B-site in the complex perovskite Pb(B,B')O3 structure were successfully grown, by using PbO-flux method. Structural, optical, dielectric, pyroelectric, piezo-electric properties of single crystals and ceramics of relaxor-based ferroelectrics such as Pb(Mg_<1/3> Nb_<2/3>)O_3(PHN), Pb(Zn_<l/3>Nb_<2/3>)O_3(PZN), Pb(In_<l/2>Nb_<l/2>)O_3(PIN), Pb(Mg_<1/2>W_<1/2>)O_3(PMW), Pb(Sc_<1/2>Ta1_<1/2>)O_3(PST) and their solid solutions with normal ferroelectric PbTiO_3(PT) and PbZrO_3(PZ), and so on have been investigated as functions of compositions, temperature, pressure, and dc-biasing fields by X-ray diffraction, polarized microscopy, Raman scattering and impedance … More gain phase analyser. We found that the volume effects(namely, the excess volume accompanied with the disordering at the B-site) play an important role in the manifestation of the relaxor behavior. Such volume and chemical effects were found to be performed by suitable substitution effects at B-site. Moreover, large ferroelectric properties such as giant spontaneous polarization, permittivity and electromechanical coupling were found to be induced by the coexistence of heterophases (many kinds of domains such as ferroelectric, antiferroelectric and relaxor / mesoscopical coexistence of microclusters/ a number of sites of polarization) near morphotropic phase boundary in relaxor-based ferroelectric solid solutions. From such coexistence in relaxor ferroelectrics, development for gradient functional ferroelectric materials (e.g., multi-functional sensor fusion) can be expected. In this work, especially, superior dielectric, pyroelectric and piezoelectric properties could be found for PIN-PT, PIN-PZ and PMW-PT solid solution systems. Less