The 0.96Na_(0.5)Bi_(0.5)TiO_(3)-0.04K_(0.5)Bi_(0.5)TiO_(3)(NKBT96/4)lead-free single crystal was successfullygrown by top-seeded solution growth method.The effective segregation coefficient for K was calculated to be 0.20.X-ray powder difraction measurement showed that the as-grown crystalpossesses rhombohedral perovskite structure at room temperature.X-ray rock curve measureindicated that the as-grown single crystal owned relatively higher quality.The NKBT96/4 singlecrystal exhibits apparent diffused dielectric behavior,where the diffusiveness index aαis 1.79 forthe[001]-oriented crystal planes.A notable thermal hysteresis,△T_(h),of 25℃was disclosed for thetetragonal antiferroelectric-tetragonal paraelectric phase transition in the dielectric propertystudies between heating and cooling.The highest remnant polarization,P_(r),16.8μC/cm^(2),wasobtained at 100℃.The electromechanical coupling coefficient k_(t)of the[001]-oriented crystalplanes at room temperat ure was determined to be 38%using resonance-antiresonance technique.The room temperature piezoelectric constant d_(33)reaches 120 pC/N.
The microstructure and coupling between structural and magnetic domains of ferromagnetic shape memory alloy Ni55Mn20.6Ga24.4 were investigated by scanning electron acoustic microscopy （SEAM）. Stripe ferroelastic domains （martensite variants） exist in every grain, and exhibit the configurations of the typical self-accommodation arrangement. Magnetic domain structure of Ni55Mn20.6Ga24.4 was observed by the Bitter method and magnetic force microscopy （MFM）. Due to the unique subsurface imaging capability of SEAM, combined with the Bitter method, the ferroelastic domain structure can be compared with in situ ferromagnetic domain structure. It is found that the martensitic variant boundaries coincide well with the ferromagnetic domain walls, which is beneficial for the understanding of the correlation between two kinds of ferroic domains.
Dielectric,hysteresis(P–E)loops and TSDC properties of transparent 85PZN–15BT ceramic over150–150℃ were investigated.The sample was found to exhibit a strong relaxor behavior and a relatively small remanent polarization.TSDC studies showed that there existed an electric field-dependent peak in the p versus T.Such interesting features were attributed to the electric field-induced transition and coexistence of polar nanoregion,long-range ordered polar region and nonpolarizable BZN-rich region.
Lizhu HuangWei ZhaoWei RuanHeji YangJiangtao ZengGuorong Li
Piezoelectric actuators operating in piezoelectric-induced strain/stress or electromechanical res.onanceinduced vibration or wave-motion friction drive mechanism have shown many advantagesover traditional electromagnetic mot ors,especilly,when miniaturizing into millimeter-scale size,while magnetoelectric act uators operating in magnetostrictive mechanism are capable of piezo-dlectric self-sensing and remote operation under an applied magnetic field.This paper summarizesthe recent progresses in piezoelectric ceramic and single crystal materials based actuators andmicromotors,ferromagnetic/ferroeletric laminated magnetoelectric actuat ors,including rotary,linear,planner,and spherical motion actuators,and bending motion magnetoelectric actuators.Their driving mechanisms,operation propertics,and applications are also explained.
<正>High Cure temperature and larger coercive field ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-P...
Wei Wang~(*1,2),Yaoyao Zhang~(1,2),Xiangyong Zhao~1,Haosu Luo~1 1 Key Laboratory of Inorganic Functional Material and Device,Shanghai Institute of Ceramics, Chinese Academy of Sciences,215 Chengbei Road,Jiading,Shanghai 201800,China 2 Graduate School of the Chinese Academy of Sciences,Beijing 100039,China
