Co离子掺杂La_(2)Ti_(2-x)Co_(x)O_(7)的室温多铁性  

Room Temperature Multiferroicity of the Co-doped La_(2)Ti_(2-x)Co_(x)O_(7)Composition

作　　者：胡博 宋笑明 徐凯 刘莹 HU Bo;SONG Xiaoming;XU Kai;LIU Ying(Henan Institute of Metrology,Zhengzhou 450000,China)

机构地区：[1]河南省计量测试科学研究院,河南郑州450000

出　　处：《信阳师范学院学报（自然科学版）》2023年第1期102-106,共5页Journal of Xinyang Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(12104415);河南省科技攻关项目(212102410003)。

摘　　要：通过向传统铁电材料La_(2)Ti_(2)O7中引入磁性Co离子,成功制备出了新型室温多铁材料La_(2)Ti_(2-x)Co_(x)O_(7)(x=0、0.03、0.05、0.07)。测试结果表明,所有样品均为单相晶体结构,在x射线探测范围内无第二相杂质出现。适当浓度的磁性Co离子掺杂不仅可有效提高材料的饱和铁磁磁化强度,还可有效降低体系漏电流,提高La_(2)Ti_(2)O7绝缘性,进而改善La_(2)Ti_(2-x)Co_(x)O_(7)铁电性和多铁性。对La_(2)Ti_(2-x)Co_(x)O_(7)等样品的顺磁、反铁磁和铁磁等复杂磁相互作用的微观机理进行了探讨。铁磁性的产生被认为与氧空位和过渡金属离子3d电子自旋之间的交换耦合作用有关。而对未掺杂的La_(2)Ti_(2)O7样品,其铁磁性的出现可能与材料内部形成的氧空位有关。由于氧空位的存在,为保持整体价态平衡,Ti^(4+)离子转变为Ti^(3+)离子,使得Ti^(3+)离子的3d轨道存在一个电子,La_(2)Ti_(2)O7样品存在弱铁磁性。The room temperature multiferroic material La_(2)Ti_(2-x)Co_(x)O_(7)(x=0,0.03,0.05,0.07)is successfully synthesized by introducing magnetic Co ions into La_(2)Ti_(2)O7.The microstructural investigation indicates that all the samples crystalize into a single phase structure and no impurity can be observed in the detected range of the X-ray diffraction.A suitable concentration of Co doping could not only enhance the magnetism,but also decrease the leakage current and increase the insulativity.As a result,the ferroelectricity and multiferroic can be improved.Simultaneously,the ferromagnetic,antiferromagnetic and paramagnetic interactions in La_(2)Ti_(2-x)Co_(x)O_(7)are also discussed.The ferromagnetism originates from the coupling interaction of the oxygen vacancies and the spins of Co cations.For the undoped La_(2)Ti_(2)O7samples,the ferromagnetism can be attributed to the oxygen vacancies.For keeping the balance of the valence,the existed oxygen vacancies cause that some Ti^(4+)ions are transformed into Ti^(3+)ions.Therefore,an electron exists in the 3d orbital of Ti^(3+)ions and weak ferromagnetism emerges in La_(2)Ti_(2)O7sample.

关 键 词：铁磁 铁电 室温 多铁性 反铁磁 

分 类 号：TM277[一般工业技术—材料科学与工程] O469[电气工程—电工理论与新技术]