Jović Orsini N, Milić M M, Torres T E
Institute of Nuclear Sciences 'Vinča', Laboratory of Theoretical Physics and Condensed Matter Physics (020), University of Belgrade, PO Box 522, RS-11001 Belgrade, Serbia.
Nanotechnology. 2020 May 29;31(22):225707. doi: 10.1088/1361-6528/ab76e7. Epub 2020 Feb 17.
In this work, we studied structural and magnetic properties of 18 nm sized Zn-substituted magnetite, 28 nm sized unsubstituted and 17 nm sized (Mn, Zn)-substituted iron oxide nanoparticles, synthesized by thermal decomposition method. Their features were examined by analyzing the x-ray diffraction data, Fe Mössbauer spectra and magnetization measurements by SQUID interferometer. The microstructure was inspected comparing the different size and strain broadening models incorporated into Fullprof software. In terms of crystallinity and size dispersion, applied synthesis protocol shows superiority over decomposition of iron oleate and the co-precipitation synthesis route. The saturation magnetization at T = 5 K was found to be within the M = 91.2-98.6 A m kg range, while at 300 K M of pure and Zn-substituted FeO nanoparticles is 83.6 and 86.2 A m kg, respectively. Effective magnetic anisotropy constant K , estimated under slow measurements by SQUID, is below 20 kJ m in all three samples. Some preliminary measurements of the magnetic hyperthermia performance, expressed via specific absorption rate value showed that the best heating performances were displayed by 18 nm sized oleic acid-coated ZnFeO cubo-octahedrons with SAR ≅ 425 W/g at H = 20 kA m and f = 228 kHz.
在这项工作中，我们研究了通过热分解法合成的尺寸为18 nm的锌取代磁铁矿、尺寸为28 nm的未取代以及尺寸为17 nm的（锰，锌）取代的氧化铁纳米颗粒的结构和磁性。通过分析X射线衍射数据、Fe穆斯堡尔谱以及利用超导量子干涉仪进行磁化测量来研究它们的特性。通过比较纳入Fullprof软件的不同尺寸和应变展宽模型来检查微观结构。在结晶度和尺寸分散方面，所应用的合成方案显示出优于油酸铁分解法和共沉淀合成路线。发现T = 5 K时的饱和磁化强度在M = 91.2 - 98.6 A m²/kg范围内，而在300 K时，纯的和锌取代的Fe₃O₄纳米颗粒的M分别为83.6和86.2 A m²/kg。通过超导量子干涉仪在慢速测量下估计的有效磁各向异性常数K在所有三个样品中均低于20 kJ/m³。通过比吸收率值表示的磁热疗性能的一些初步测量表明，尺寸为18 nm的油酸包覆的ZnFe₂O₄立方八面体在H = 20 kA/m和f = 228 kHz时具有最佳加热性能，比吸收率SAR≅425 W/g。
