Abdel-Baset T A, Fang Yue-Wen, Anis B, Duan Chun-Gang, Abdel-Hafiez Mahmoud
Faculty of Science, Physics Department, Fayoum University, Fayoum, 63514, Egypt.
Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200241, China.
Nanoscale Res Lett. 2016 Dec;11(1):115. doi: 10.1186/s11671-016-1332-x. Epub 2016 Feb 29.
The ability to produce high-quality single-phase diluted magnetic semiconductors (DMS) is the driving factor to study DMS for spintronics applications. Fe-doped ZnO was synthesized by using a low-temperature co-precipitation technique producing Zn 1-x Fe x O nanoparticles (x= 0, 0.02, 0.04, 0.06, 0.08, and 0.1). Structural, Raman, density functional calculations, and magnetic studies have been carried out in studying the electronic structure and magnetic properties of Fe-doped ZnO. The results show that Fe atoms are substituted by Zn ions successfully. Due to the small ionic radius of Fe ions compared to that of a Zn ions, the crystal size decreases with an increasing dopant concentration. First-principle calculations indicate that the charge state of iron is Fe (2+) and Fe (3+) with a zinc vacancy or an interstitial oxygen anion, respectively. The calculations predict that the exchange interaction between transition metal ions can switch from the antiferromagnetic coupling into its quasi-degenerate ferromagnetic coupling by external perturbations. This is further supported and explains the observed ferromagnetic bahaviour at magnetic measurements. Magnetic measurements reveal that decreasing particle size increases the ferromagnetism volume fraction. Furthermore, introducing Fe into ZnO induces a strong magnetic moment without any distortion in the geometrical symmetry; it also reveals the ferromagnetic coupling.
能够制备出高质量的单相稀磁半导体（DMS）是研究用于自旋电子学应用的DMS的驱动因素。采用低温共沉淀技术合成了Fe掺杂的ZnO，制备出了Zn1-xFexO纳米颗粒（x = 0、0.02、0.04、0.06、0.08和0.1）。在研究Fe掺杂ZnO的电子结构和磁性时进行了结构、拉曼、密度泛函计算和磁性研究。结果表明，Fe原子成功地被Zn离子取代。由于Fe离子的离子半径比Zn离子小，晶体尺寸随着掺杂浓度的增加而减小。第一性原理计算表明，铁的电荷态分别为带有锌空位或间隙氧阴离子的Fe(2+)和Fe(3+)。计算预测，通过外部扰动，过渡金属离子之间的交换相互作用可以从反铁磁耦合转变为准简并铁磁耦合。这进一步得到了支持，并解释了在磁性测量中观察到的铁磁行为。磁性测量表明，减小颗粒尺寸会增加铁磁体积分数。此外，将Fe引入ZnO会诱导出强磁矩，而不会使几何对称性发生任何畸变；这也揭示了铁磁耦合。
