Spinel ferrite nanoparticles are widely studied to evaluate their suitability in many applications. Magnetic, electrical, optical, and catalytic properties of spinel ferrites nanoparticles depend on: i) intrinsic property such as cation distribution among tetrahedral (A-site) and octahedral ligand (B-site) sublattices in spinel structure and ii) extrinsic properties such as specific surface area and particle size distribution of nanoparticles. To enhance the above properties by modifying both the intrinsic and extrinsic parameters, narrow size distributed Mg_0.7Zn_0.3Fe₂O₄ mixed spinel ferrite nanoparticles are synthesized by the solvothermal reflux method using high boiling point reflux solvents. The particles are crystallized in a cubic spinel structure and are single crystallites with an average particle diameter of 12 nm, measured from an electron micrograph. The temperature-dependent dielectric constant $(\varepsilon^{\prime})$ and dielectric loss $(\varepsilon^{\prime \prime})$ of the sample show no change below 290 °C and increase with temperature up to 450 °C. Both $\varepsilon^{\prime}$ and $\varepsilon^{\prime}$ decrease with the increase of electric field frequency and shows dominant space charge polarization at grain boundaries. The DC conductivity estimated from impedance spectra (Cole–Cole plot) shows the Arrhenius model electron hopping conductivity mechanism above 390 °C. Nanoparticles show high Ms (57.41 emu/g) than that synthesized by other methods. The sample shows the magnetic hyperthermia value of 189 W/g at 1 mg/mL concentration. The sample degraded 95% of rhodamine B dye in water in 320 min under UV light illumination. Some of these properties are superior to Mg_0.7Zn_0.3Fe₂O₄ nanoparticles synthesized by other wet chemical and/or ball milling methods.

中文翻译：

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Mg0.7Zn0.3Fe2O4纳米晶的介电、磁热和光催化性能

尖晶石铁氧体纳米颗粒被广泛研究以评估它们在许多应用中的适用性。尖晶石铁氧体纳米粒子的磁性、电学、光学和催化性能取决于：i) 固有属性，例如尖晶石结构中四面体（A 位）和八面体配体（B 位）亚晶格之间的阳离子分布和 ii) 外部属性，例如纳米颗粒的比表面积和粒径分布。为了通过修改内在和外在参数来增强上述性能，窄尺寸分布的 Mg _0.7 Zn _0.3 Fe ₂ O ₄使用高沸点回流溶剂通过溶剂热回流法合成混合尖晶石铁氧体纳米颗粒。颗粒以立方尖晶石结构结晶，是单晶，平均粒径为 12 nm，由电子显微照片测量。随温度变化的介电常数 $(\varepsilon^{\prime})$ 和介电损耗 $(\varepsilon^{\prime \prime})$ 样品在 290 °C 以下没有变化，随着温度升高到 450 °C。两个都 $\varepsilon^{\prime}$ 和 $\varepsilon^{\prime}$ 随电场频率的增加而减小，并在晶界处显示出占主导​​地位的空间电荷极化。从阻抗谱（Cole-Cole 图）估计的 DC 电导率显示 Arrhenius 模型电子跳跃电导率机制高于 390 °C。纳米颗粒显示出比其他方法合成的更高的 Ms (57.41 emu/g)。样品显示 1 mg/mL 浓度的磁热疗值为 189 W/g。在紫外光照射下，样品在 320 分钟内降解了水中 95% 的罗丹明 B 染料。这些特性中的一些优于通过其他湿化学和/或球磨方法合成的Mg _0.7 Zn _0.3 Fe ₂ O ₄纳米粒子。