良好的抗极性疲劳能力对于提高压电元器件可靠性、稳定性、延长其寿命至关重要。前期我们生长了压电性和热稳定性优异的三元Pb(Sc1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3（PSN-PMN-PT）新型弛豫铁电单晶。明确点缺陷、晶格结构、电畴对极性疲劳的影响规律是改善该体系抗极性疲劳能力的关键。本申请拟以PSN-PMN-PT为研究对象，通过不同原子占位受主（Mn2+、Co3+取代Ti4+;K+取代Pb2+）和施主（V5+取代Ti4+;La3+取代Pb2+）掺杂调控材料内部点缺陷。结合光电子能谱(XPS)与电性能测量技术对点缺陷种类和浓度进行鉴别与半定量计算；系统研究点缺陷种类、浓度、迁移与复合对晶格结构、电畴形貌的微观调控；在实验基础上，结合理论分析，探索“点缺陷---晶格结构---电畴---极性疲劳”之间的关联规律，寻求提高抗极性疲劳能力的调控方法，理解极性疲劳的起源

A good fatigue resistance of piezoelectric device plays a significant role in improving its performances (such as reliability, stability and even prolonging lifetime). In our previous research, a new Pb(Sc1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PSN-PMN-PT) relaxor ferroelectric single crystal was fabricated, which exhibits an excellent piezoelectric property and thermal stability. The influence of point defect, lattice structure and domain on polarity fatigue is the key to enhance the fatigue resistance. Therefore, a targeted control of inner point defects in PSN-PMN-PT crystal induced by acceptor/donor doping in different sites, especially Mn2+/Co3+ substitutional Ti4+, K+ substitutional Pb2+, V5+ substitutional Ti4+, and La3+ substitutional Pb2+, can be carried out for the high-quality material. Meanwhile, the type of point defects and their concentrations are characterized and identified by photoelectron spectroscopy (XPS) combined with electrical measurements. The effects of the type, concentration, migration and recombination of point defects on lattice structure and domain morphology are thorough investigated. Finally, the relationships of polarity fatigue with point defect, lattice structure, and domain are explored on the basis of the experimental and theoretical analyses. As a consequence, it is possible to realize the effective control of improving anti-fatigue and then to reveal the nature of fatigue with the corresponding mechanism.