Bismuth zinc niobate:BZN-BT,a new lead-free BaTiO_(3)-based ferroelectric relaxor?  

作　　者：Jessica Marshall David Walker Pam Thomas 

机构地区：[1]Department of Physics,University of Warwick,Gibbet Hill Road,Coventry,CV47AL,UK

出　　处：《Journal of Advanced Dielectrics》2020年第6期69-80,共12页先进电介质学报（英文）

摘　　要：The novel lead-free ferroelectric relaxor system x(Bi(Zn_(2/3) Nb_(1/3))O_(3))(1−x)BaTiO3(xBZN(1−x)BT)has received interest as a high-capacity relaxor dielectric material.Small quantities(<10.0 mol.%)of BZN-based dopant had significant impacts on the structure of the BaTiO_(3) host.This study evaluates the effect of BZN additions to the BaTiO_(3) host up to xBZN=10.0%.Initial additions of BZN were observed to stabilize tetragonal and orthorhombic coexistence at 295 K,alongside increasing dielectric constant.Peak dielectric constant and polarization were observed at x<4.0%,coinciding with maximum orthorhombic intensity and a local minima in tetragonal intensity.Compositions 0<x<4.0%showed increasing polarization and a drop in Tm and classi-cal ferroelectric properties.No significant dielectric dispersion was observed for compositions x<4.0%over the frequency range 5-640 kHz.Compositions at x>4.0%showed the onset of dielectric relaxation alongside a drop in polarization coincident with a drop in the tetragonal c_(T)/a_(T) ratio and the onset of the cubic phase at 295 K.Peak piezoelectric,dielectric and polarization values occurred over the range 3.8%<x<4.0%,alongside maximum orthorhombic intensity.Subsequent BZN additions showed a rapid onset of dielectric relaxation,alongside an increase in cubic intensity and a continuous drop in T_(m) with a minima near x=7.0%.Tetragonal presence at 295 K also vanished to zero at x=7.0%.Polarization loops ceased showing ferroelectric characteristics at x>5.0%,showing a transition from lossy relaxor dielectric to low-loss relaxor dielectric at x>10.0%.

关 键 词：RELAXORS lead-free ferroelectrics CRYSTALLOGRAPHY PIEZOELECTRICS dielectrics 

分 类 号：TB3[一般工业技术—材料科学与工程]