(K_(0.5)Na_(0.5))NbO_(3)-xBi(Co_(0.875)Fe_(0.125))O_(3)多铁陶瓷的相变及其铁电性和铁磁性

Phase Transition,Ferroelectricity and Ferromagnetism of(KNa)NbOBi(CoFe)O Multiferroic Ceramics

采用固相反应烧结法合成了(K_(0.5)Na_(0.5))NbO_(3)-xBi(Co_(0.875)Fe_(0.125))O_(3)(KNN-xBCF)多铁陶瓷,并且对其结构和光电磁等特性进行了系统的研究。结果表明,随着BCF组分x的增加,KNN-xBCF陶瓷表现出明显的由正交相向菱形相的结构转变行为,而且其光学带隙也被降低到了3 eV。此外,源于正交相和菱形相的共存,KNN-0.01BCF陶瓷拥有最大的剩余极化强度,约为4.02μC/cm^(2)。同时,KNN-xBCF陶瓷的磁性可以由抗磁性转化为铁磁性,从而实现铁电性与铁磁性的共存。系统研究了无铅钙钛矿多铁KNN-xBCF陶瓷的结构相变、带隙窄化、铁电性和铁磁性,并且展示了其在多铁器件中的潜在应用。

(K_(0.5)Na_(0.5))NbO_(3)-xBi(Co_(0.875)Fe_(0.125))O_(3)(KNN-xBCF)multiferroic ceramics were synthesized by the solid state reaction sintering method,and the structure,optical,electrical and magnetic properties of the ceramics were systematically investigated.The results indicate that with the increase of BCF component x,KNN-xBCF ceramics exhibit obviously a structural transition behaviour from the orthorhombic phase to rhombohedral phase,and the optical band gap of KNN-xBCF ceramics is reduced to 3 eV.In addition,originating from the coexistence of the orthorhombic phase and rhombohedral phase,the KNN-0.01 BCF ceramics have the highest remanent polarization of about 4.02μC/cm^(2).Meanwhile,the magnetism of KNN-xBCF ceramics can be converted from diamagnetism to ferromagnetism,thus realizing the coexistence of ferroelectricity and ferromagnetism.The structure phase transition,band gap narrowing,ferroelectricity and ferromagnetism of lead-free perovskite multiferroic KNN-xBCF ceramics were systematically researched,and the potential applications of KNN-xBCF ceramics in multiferroic devices were demonstrated.