Wang Jin-Feng, Shi Teng-Fei, Zhuang Zhao-Tong, Gao Qian-Qian, Zhang Yan-Ming
College of Physics and Materials Science, National Demonstration Center for Experimental Physics Education, Henan Normal University, Henan Key Laboratory of Photovoltaic Materials Xinxiang 453007 China
RSC Adv. 2018 Aug 14;8(51):29071-29077. doi: 10.1039/c8ra05755a.
The itinerant electron density () near the Fermi level has a close correlation with the physical properties of SrFeMoO. Two series of single-phase SrNa FeMoO ( = 0.1, 0.2, 0.3) and SrNa FeMoO ( = 2; = 0.1, 0.2, 0.3) ceramics were specially designed and the itinerant electron density () of them can be artificially controlled to be: = 1 - and = 1 - + 3 = 1 + 0.5, respectively. The corresponding crystal structure, magnetization and the ferromagnetic Curie temperature ( ) of two subjects were investigated systematically. The X-ray diffraction analysis indicates that SrNa FeMoO ( = 0.1, 0.2, 0.3) have comparable Fe/Mo anti-site defect (ASD) content in spite of decreased . However, a drastically improved Fe/Mo ASD can be observed in SrNa FeMoO ( = 2; = 0.1, 0.2, 0.3) caused by the intrinsic wrong occupation of normal Fe sites with excess Mo. Magnetization-magnetic field (-) behavior confirms that it is the Fe/Mo ASD not that dominantly determines the magnetization properties. Interestingly, approximately when ≤ 0.9, of SrNa FeMoO ( = 0.1, 0.2, 0.3) exhibits an overall increase with decreasing , which is contrary to the response in electron-doped SFMO. Such abnormal is supposed to relate with the ratio variation of (Mo)/(Fe). Moreover, when ≥ 1, of SrNa FeMoO ( = 2; = 0.3) exhibits a considerable rise of about 75 K over that of SrNa FeMoO ( = 2; = 0.1), resulting from improved caused by introducing excess Mo into SrNa FeMoO. Maybe, our work can provide an effective strategy to artificially control and ferromagnetic accordingly, and provoke further investigation on the FeMo-baseddouble perovskites.
费米能级附近的巡游电子密度（）与SrFeMoO的物理性质密切相关。特别设计了两组单相SrNa FeMoO（ = 0.1、0.2、0.3）和SrNa FeMoO（ = 2； = 0.1、0.2、0.3）陶瓷，它们的巡游电子密度（）可人为控制为：分别为 = 1 - 和 = 1 - + 3 = 1 + 0.5。系统研究了这两组样品相应的晶体结构、磁化强度和铁磁居里温度（）。X射线衍射分析表明，尽管 降低，但SrNa FeMoO（ = 0.1、0.2、0.3）具有相当的Fe/Mo反位缺陷（ASD）含量。然而，在SrNa FeMoO（ = 2； = 0.1、0.2、0.3）中观察到Fe/Mo ASD显著改善，这是由于过量的Mo对正常Fe位点的固有错误占据所致。磁化强度 - 磁场（ - ）行为证实，主要决定磁化性质的是Fe/Mo ASD而非 。有趣的是，当 ≤ 0.9时，SrNa FeMoO（ = 0.1、0.2、0.3）的 总体上随 降低而增加，这与电子掺杂的SFMO中的 响应相反。这种异常的 应该与（Mo）/（Fe）的比例变化有关。此外，当 ≥ 1时，SrNa FeMoO（ = 2； = 0.3）的 比SrNa FeMoO（ = 2； = 0.1）显著升高约75 K，这是由于向SrNa FeMoO中引入过量Mo导致 改善所致。也许，我们的工作可以提供一种有效的策略来相应地人为控制 和铁磁 ，并引发对FeMo基双钙钛矿的进一步研究。
