Room temperature ferromagnetism and half metallicity in nickel doped ZnS: Experimental and DFT studies
Room temperature ferromagnetism and half metallicity in nickel doped ZnS: Experimental and DFT studies
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DOI：
10.1016/j.matchemphys.2015.05.016
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发表时间：
2015-06-15
影响因子：
4.6
通讯作者：
Naseem, Shahzad
中科院分区：
文献类型：
--
作者：
Akhtar, Muhammad Saeed;Malik, Mohammad Azad;Naseem, Shahzad
采用化学浴沉积法（CBD）在玻璃衬底上制备了掺杂镍的纳米晶ZnS薄膜。采用CBD/共沉淀法合成了ZnS:Ni纳米颗粒。粉末x射线衍射（p-XRD）研究表明，薄膜和纳米颗粒都对应于ZnS的闪锌矿（立方）相，由于镍在ZnS晶格中的掺入，其28值向较高的方向轻微偏移。根据Scherrer方程，ZnNiS薄膜和纳米颗粒的晶粒尺寸分别为4 nm和2.6 nm。扫描电子显微镜（SEM）图像显示，薄膜的形貌是基于纳米尺度的准球形颗粒。能量色散x射线（EDX）光谱证实，沉积薄膜具有与镍掺杂ZnS一致的化学计量学。采用基于自旋极化密度泛函理论（DFT）的全势线性化增广平面波（FP-L/APW）方法研究掺杂浓度下ZnNiS的电子和磁性能。采用广义梯度近似（GGA + U）方法研究交换相关泛函。电子能带结构和态密度（DOS）在铁磁交换相互作用下表现出100%的自旋极化（半金属丰度）。超导量子干涉器件（SQUID）分析证实了镍掺杂ZnS铁磁性的理论观察。这些基于ZnS的半金属铁磁体在未来的自旋电子器件中具有良好的应用前景。(C) 2015 Elsevier B.V.版权所有
The nickel doped nanocrystalline ZnS thin films were deposited onto glass substrates by chemical bath deposition (CBD). Also ZnS:Ni nanoparticles were synthesized by CBD/co-precipitation method. Powder X-ray diffraction (p-XRD) studies demonstrate that both thin films and nanoparticles correspond to sphalerite (cubic) phase of ZnS with slight shift towards higher 28 values due to incorporation of nickel in the ZnS lattice. The crystallite sizes estimated by Scherrer equation were 4 and 2.6 nm for ZnNiS thin films and nanoparticles, respectively. Scanning Electron Microscopy (SEM) images reveal that the morphology of thin films is based on quasi-spherical particles with nano scale dimensions. Energy Dispersive X-ray (EDX) spectroscopy confirms that the as-deposited thin films have a stoichiometry consistent with the nickel doped ZnS. Full-potential linearized augmented plane wave (FP-L/APW) method based on spin-polarized density functional theory (DFT) was employed to investigate the electronic and magnetic properties of ZnNiS for the doping concentration. Exchange-correlation functional was studied using generalized gradient approximation (GGA + U) method. Electronic band structures and density of states (DOS) demonstrate 100% spin polarization (half metallicity) with ferromagnetic exchange interactions. Superconducting quantum interference device (SQUID) analysis confirms the theoretical observation of ferromagnetism in nickel doped ZnS. These ZnS based half metallic ferromagnets seem to have virtuous applications in future spintronic devices. (C) 2015 Elsevier B.V. All rights reserved.