Abstract Spinel ferrite with the general formula Mn1−xCuxFe1.85Gd0.15O4 (x = 0.2, 0.4, 0.6 and 0.8) was synthesized using the standard sonochemical method. The structure, optical, morphology, dielectric and magnetic properties of the prepared Mn1−xCuxFe1.85Gd0.15O4 nanoferrites were exhaustively investigated using various characterization techniques. The phase purity, secondary phase and crystallite parameters were studied from X-ray diffraction patterns. Fourier transform infrared spectra showed two absorption bands of transition metal oxides in the frequency range from 400 to 650 cm−1, which are related to asymmetric stretching modes of the spinel ferrites (AB2O4). Raman spectra have five active modes illustrating the vibration of O2− ions at both tetrahedral (A) site and octahedral (B) site ions. The wide and narrow scan spectrum from X-ray photoelectron spectroscopy results confirmed the presence of Mn, Cu, Gd, Fe, C and O elements in the composition. The oxidation state and core level of the photo electron peaks of Mn 2p, Cu 2p, Gd 3d, Fe 2p and O 1s were analyzed. The influence of the Cu2+ concentration in Mn1−xCuxFe1.85Gd0.15O4 on the morphology, varying from nanorods, nanoflakes to spherical, was explored on the basis of scanning electron microscopy images. Ultraviolet diffuse reflectance spectroscopy studies indicated that the optical bandgap (5.12–5.32 eV) of the nanoferrites showed an insulating behavior. The dielectric constant, loss tangent and complex dielectric constant values decreased with an increase in frequency with the addition of Gd3+ content. A vibrating sample magnetometer showed that the prepared nanoferrites had a soft ferromagnetic nature. The magnetic parameter changed markedly with an increase in the Cu content in Mn1−xCuxFe1.85Gd0.15O4 nanoferrites. The optical, dielectric and magnetic properties were considerably enhanced with the addition of Gd3+ ions in the spinel nanoferrites.

中文翻译：

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添加钆的 Mn-Cu 纳米铁氧体的结构、光学、介电和磁性研究

摘要 使用标准声化学方法合成了通式为 Mn1−xCuxFe1.85Gd0.15O4 (x = 0.2、0.4、0.6 和 0.8) 的尖晶石铁氧体。使用各种表征技术对制备的 Mn1−xCuxFe1.85Gd0.15O4 纳米铁氧体的结构、光学、形态、介电和磁性能进行了详尽的研究。从 X 射线衍射图研究相纯度、第二相和微晶参数。傅里叶变换红外光谱在 400 到 650 cm-1 的频率范围内显示了两个过渡金属氧化物的吸收带，这与尖晶石铁氧体 (AB2O4) 的不对称拉伸模式有关。拉曼光谱具有五种活性模式，说明了四面体 (A) 位点和八面体 (B) 位点离子处 O2− 离子的振动。X 射线光电子能谱结果的宽窄扫描光谱证实了组合物中存在 Mn、Cu、Gd、Fe、C 和 O 元素。分析了Mn 2p、Cu 2p、Gd 3d、Fe 2p 和O 1s 的光电子峰的氧化态和核心能级。基于扫描电子显微镜图像探索了 Mn1−xCuxFe1.85Gd0.15O4 中 Cu2+ 浓度对形态的影响，从纳米棒、纳米薄片到球形。紫外漫反射光谱研究表明，纳米铁氧体的光学带隙 (5.12–5.32 eV) 显示出绝缘行为。随着Gd3+含量的增加，介电常数、损耗角正切和复介电常数值随着频率的增加而降低。振动样品磁强计表明制备的纳米铁氧体具有软铁磁性。随着Mn1−xCuxFe1.85Gd0.15O4 纳米铁氧体中Cu 含量的增加，磁性参数发生显着变化。通过在尖晶石纳米铁氧体中添加 Gd3+ 离子，光学、介电和磁性能得到显着增强。