Zeng Xue, Hou Zhipeng, Ju Jiaqi, Gao Lei, Zhang Junwei, Peng Yong
School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China.
Guangdong Provincial Key Laboratory of Optical Information Material and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China.
Materials (Basel). 2022 Mar 25;15(7):2422. doi: 10.3390/ma15072422.
Determining the exact occupation sites of the doping ions in spinel ferrites is vital for tailoring and improving their magnetic properties. In this study, the distribution and occupation sites of cations in MgFeO and Zn-doped MgFeO ferrite are imaged by Cs-STEM. The experimental STEM images along [001], [011] and [111] orientations suggest that the divalent Mg cations occupy all A sites, and the trivalent Fe cations occupy all B sites in MgFeO ferrite prepared by electrospinning, which is consistent with the normal spinel structure. We further clarify that the preferred sites of dopant Zn ions are Fe crystallographic sites in the Zn-doped MgFeO ferrite nanofibers. Magnetic measurements show that Zn doping affects the spin states of the Fe, and the Fe-O-Fe super-exchange interaction leads to enhancements in the magnetization and reduction in the Curie temperature. Our work should contribute a significant step toward eventually realizing the practical application of doped spinel ferrites.
确定掺杂离子在尖晶石铁氧体中的精确占据位置对于定制和改善其磁性能至关重要。在本研究中，通过Cs-STEM对MgFeO和Zn掺杂的MgFeO铁氧体中阳离子的分布和占据位置进行成像。沿[001]、[011]和[111]取向的实验STEM图像表明，二价Mg阳离子占据所有A位，三价Fe阳离子占据通过静电纺丝制备的MgFeO铁氧体中的所有B位，这与正常尖晶石结构一致。我们进一步阐明，掺杂剂Zn离子在Zn掺杂的MgFeO铁氧体纳米纤维中的优先占据位置是Fe晶体学位置。磁性测量表明，Zn掺杂影响Fe的自旋态，并且Fe-O-Fe超交换相互作用导致磁化强度增强和居里温度降低。我们的工作应为最终实现掺杂尖晶石铁氧体的实际应用迈出重要一步。
