Designing electromagnetic materials, particularly those based on transition-metal-containing spinel ferrites, with a controlled structure, phase, and chemistry at the nanoscale dimensions while realizing enhanced electrical and magnetic properties continues to be a challenging problem. Herein, we report on the synthesis and structure–property correlation of dysprosium (Dy)-substituted iron-rich cobalt ferrite (Co_0.8Fe_2.2–xDy_xO₄; CFDO; x = 0.000–0.100) oxides with variable Dy³⁺ concentration. Chemical bonding analyses of CFDO nanomaterials using Raman spectroscopic analyses supported the spinel phase formation with high quality. Cation distribution determined from Mössbauer spectroscopy reveals the fact that Dy³⁺ occupies the octahedral site of the spinel lattice. Saturation magnetization (M_s) values calculated using Neel’s two-sublattice model and cation distribution derived from Mossbauer’s studies correlate well with the magnetization values obtained from SQUID measurements. The B-site hyperfine field decreases from 52.24 ± 0.10 to 49.26 ± 0.00 T, as evidenced by the Mössbauer spectra, with Dy substitution, which decreases the Fe-ion occupancy from the octahedral site of CFDO. Frequency-dependent dielectric constant indicates electron hopping in the grain interior, which ceases above 6.3 kHz. Dielectric measurements indicate that these CFDO compounds are useful for absorption at higher frequencies. Thus, using the combined approach based on Raman and Mössbauer spectroscopic analyses, the present work elucidates the structure, chemical bonding, and magnetic properties of Dy-substituted Fe-rich cobalt ferrite. CFDO may serve as a model system to apply to a class of Fe-rich ferromagnetic nanomaterials for electromagnetic and sensor applications.

中文翻译：

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Dy3+取代富铁钴铁氧体阳离子分布与磁介电性能的相关性

设计电磁材料，特别是那些基于含过渡金属的尖晶石铁氧体，在纳米尺度上具有可控的结构、相和化学性质，同时实现增强的电磁性能仍然是一个具有挑战性的问题。在此，我们报告了镝 (Dy) 取代的富铁钴铁氧体（Co _0.8 Fe _{2.2– x} Dy _x O ₄；CFDO；x = 0.000–0.100）具有可变 Dy ^{3+的氧化物的合成和结构-性质相关性}专注。使用拉曼光谱分析对 CFDO 纳米材料进行的化学键合分析支持高质量的尖晶石相形成。从穆斯堡尔谱测定的阳离子分布揭示了 Dy ³⁺占据尖晶石晶格的八面体位置这一事实。饱和磁化强度 ( M _s) 使用 Neel 的双亚晶格模型和从穆斯堡尔的研究中得出的阳离子分布计算的值与从 SQUID 测量中获得的磁化强度值密切相关。B 位点超精细场从 52.24 ± 0.10 T 降低到 49.26 ± 0.00 T，如穆斯堡尔光谱所证明的那样，Dy 取代降低了 CFDO 八面体位点的 Fe 离子占有率。频率相关的介电常数表明电子在颗粒内部跳跃，在 6.3 kHz 以上停止。介电测量表明这些 CFDO 化合物可用于吸收较高频率。因此，使用基于拉曼和穆斯堡尔光谱分析的组合方法，目前的工作阐明了 Dy 取代的富铁钴铁氧体的结构、化学键合和磁性。