The doping of Cr ions on the structure, optical and magnetic properties of ZnO have been investigated. Zn_1−xCr_xO (0 ≤ x ≤ 0.05) samples were prepared by the solution combustion method. Rietveld refined x-ray diffraction results reveal that all the samples are in a hexagonal structure. Transmission electron microscopy (TEM) revealed that the particle size was 48$\pm$ nm, 29 $\pm$ nm and 25 $\pm$ nm for the Zn_1−xCr_xO with x = 0, 0.03 and 0.05, respectively. The band-gap decreases slightly from 3.308 $\pm$ 0.003 eV to 3.291 $\pm$ 0.003 eV with increase of Cr content from x = 0 to 0.05, respectively. The field-dependent magnetization M(μ_οH) measurements of ZnO and Cr-doped ZnO exhibit room temperature ferromagnetism (RTFM). Photoluminescence and electron paramagnetic resonance exhibits negatively charged zinc vacancies ($V_{\mathrm{Zn}}^{-})$ and singly ionized oxygen vacancies ($V_{\mathrm{o}}^{+}$) in ZnO and these defects are responsible for RTFM. And the $V_{\mathrm{Zn}}^{-}$ accountable for RTFM in Cr-doped ZnO. EPR results confirmed that Cr³⁺ ions replaces the Zn²⁺ sites in the hexagonal ZnO. The observed long-range ferromagnetism ordering is explained based on the bound magnetic polaron (BMP) mechanism. This work elucidates the origin of RTFM in synthesized ZnO and Cr-doped ZnO.

研究了 Cr 离子掺杂对 ZnO 结构、光学和磁学性质的影响。Zn _{1− x} Cr _x O (0 ≤ x ≤ 0.05) 样品采用溶液燃烧法制备。Rietveld 精修 X 射线衍射结果表明所有样品均呈六方结构。透射电子显微镜 (TEM) 显示粒径为 48$\pm$纳米，29$\pm$纳米和 25$\pm$Zn _{1− x} Cr _x O 的 nm 分别为x = 0、0.03 和 0.05。带隙从 3.308 略微下降$\pm$0.003  eV 至 3.291$\pm$0.003  eV，Cr 含量分别从x = 0 增加到 0.05。ZnO 和 Cr 掺杂 ZnO 的场相关磁化强度M (μ _ο H ) 测量表现出室温铁磁性 (RTFM)。光致发光和电子顺磁共振表现出带负电的锌空位（$V_{\mathrm{锌}}^{-})$和单电离氧空位（$V_{\mathrm{o}}^{+}$) 在 ZnO 中，这些缺陷是造成 RTFM 的原因。和$V_{\mathrm{锌}}^{-}$负责 Cr 掺杂 ZnO 中的 RTFM。EPR 结果证实，Cr ³⁺离子取代了六方 ZnO 中的Zn ^2+位置。基于束缚磁极化子 (BMP) 机制解释了观察到的长程铁磁性排序。这项工作阐明了 RTFM 在合成 ZnO 和 Cr 掺杂 ZnO 中的起源。