Abstract Microwave irradiation method is employed to synthesis of Zn1−xCoxO (x = 0.001–0.004) nanoparticles and investigate their structural, optical and magnetic properties using various characterization techniques. Structural studies reveal single phase hexagonal structure with average crystallite size 18–28 nm. FTIR study identifies the functional group present in the samples. The incorporation of Co2+ ions into the ZnO lattice is confirmed through XRD and UV–Vis studies. PL spectra exhibit a strong emission peak in UV region and a defect related visible emission peak in orange red region. These peaks are attributed to near band edge emission and the presence of oxygen related defects in the samples respectively. The blue shift observed in the UV emission peak shows an increase in the carrier concentration caused by the interstitial incorporation of ions into the ZnO lattice. The oxygen related defect is also confirmed through a peak obtained around g factor 1.9933 in ESR studies. Further, the number of spin contributing the ESR signal demonstrates the dependence of the strength of ferromagnetism on the concentration of oxygen ion vacancies. The VSM, ESR and PL measurements confirm the origin of RTFM of Co doped ZnO nanoparticles from the exchange interaction between the localized spin moments resulting from oxygen vacancies. The reason for the obtained super paramagnetic nature for x = 0.002 and x = 0.003 may be either due to some of nanoparticles or due to the weakly coupled Co ions in the Zn2+ site in the ZnO lattice. Further, the ferromagnetic behavior arises again for x = 0.004 due to the incorporation of Co2+ ions in the interstitial positions.

中文翻译：

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Co掺杂ZnO DMS纳米粒子的结构、光学和磁学性质的微波辐射法

摘要 采用微波辐射法合成 Zn1−xCoxO (x = 0.001–0.004) 纳米粒子，并使用各种表征技术研究它们的结构、光学和磁性特性。结构研究揭示了单相六方结构，平均晶粒尺寸为 18-28 nm。FTIR 研究确定了样品中存在的官能团。通过 XRD 和 UV-Vis 研究证实了 Co2+ 离子掺入到 ZnO 晶格中。PL 光谱在紫外区表现出强发射峰，在橙红色区表现出与缺陷相关的可见发射峰。这些峰分别归因于近带边缘发射和样品中与氧相关的缺陷的存在。在紫外发射峰中观察到的蓝移表明，由于离子间隙结合到 ZnO 晶格中，载流子浓度增加。在 ESR 研究中，通过在 g 因子 1.9933 附近获得的峰值也证实了与氧相关的缺陷。此外，贡献 ESR 信号的自旋数证明了铁磁性强度对氧离子空位浓度的依赖性。VSM、ESR 和 PL 测量证实了 Co 掺杂的 ZnO 纳米粒子 RTFM 的起源来自氧空位引起的局部自旋矩之间的交换相互作用。x = 0.002 和 x = 0.003 获得超顺磁性的原因可能是由于一些纳米粒子或由于 ZnO 晶格中 Zn2+ 位点中的弱耦合 Co 离子。更多，