Effect of Gd doping on the structural, optical band-gap, dielectric and magnetic properties of ZnO nanoparticles

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• 作者：A. Franco Jr ; ^{franco@ufg.br} ; H.V.S. Pessoni
• 关键词：Zinc oxide ; Gd-doped ZnO ; DMS ; Room temperature ferromagnetism ; Combustion reaction method
• 刊名：Physica B: Condensed Matter
• 出版年：2017
• 出版时间：1 February 2017
• 年：2017
• 卷：506
• 期：Complete
• 页码：145-151
• 全文大小：3632 K
• 卷排序：506

文摘

Nanostructured Zn1−xGdxOδZn1−xGdxOδ (0≤x⩽0.020≤x⩽0.02) powders were synthesized by the combustion reaction method (CR) with the purpose to investigate the effect of GdGd doping on the structural, optical band-gap, dielectric and magnetic properties at room temperature. The structure and morphology of all samples were characterized by X-ray diffraction (XRD), and transmission electron microscope (TEM). The XRD patterns of all samples exhibited sharp and intensive peaks of hexagonal wurtzite structure of ZnO without any evidence of spurious crystalline phases. The nanoparticles crystalized in roughly spherical morphology with bimodal particle size distribution centered at ∼30∼30, ∼100∼100 and ∼70∼70, ∼160nm for undoped and GdGd – doped ZnO (x=0.02), respectively. Diffuse reflectance spectrum of each sample was obtained by using a UV/VIS/Near spectrometer and the optical band-gap, Eg, values decreased with increasing GdGd doping concentration; being ∼3.23∼3.23, and ∼3.17eV for x=0 and 0.02, respectively at room temperature. This red shift on the band-gap was discussed in terms of new band levels below the conducting band. Also, the dielectric permittivity data of all samples could be evaluated by the Cole– Cole model. Seems that both oxygen vacancies (VO) or/and interstitial oxygen (O″ı¨) defects present in the GdGd – doped ZnO samples play an important rule in the dielectric permittivity at room temperature. Furthermore, all GdGd – doped ZnO samples exhibited typical paramagnetic behavior at rom temperature.