Zeleňák V, Zeleňáková A, Kapusta O, Hrubovčák P, Girman V, Bednarčík J
Department of Inorganic Chemistry, Faculty of Sciences, P. J. Safarik University in Kosice Moyzesova 11 04054 Košice Slovakia.
Department of Condensed Matter Physics, Faculty of Sciences, P. J. Safarik University in Kosice Park Angelinum 9 04054 Košice Slovakia
RSC Adv. 2019 Jan 28;9(7):3679-3687. doi: 10.1039/c8ra05576a. eCollection 2019 Jan 25.
Fine FeO and GdO magnetic nanoparticles (NPs) with sizes 7 nm and 10 nm embedded into mesoporous silica have been prepared using a wet-impregnation method. A comparative study of the reactant concentration along with the hosting matrix symmetry on mesostructuring and the magnetic properties of the nanocomposites have been investigated. Reactants with four different concentrations of Fe and Gd ions and silica matrices with two different kinds of symmetry (hexagonal and cubic) have been utilized for the study. The structural characterization of the samples has been carried out by the N adsorption/desorption method, high-energy X-ray diffraction (HE-XRD), TG/DTA, and high resolution transmission electron microscopy (HRTEM). The magnetic properties of the nanocomposites have been examined by means of SQUID magnetometry. It has been found that a range of different magnetic states (diamagnetic, paramagnetic, ferromagnetic, superparamagnetic) can be induced by the feasible tailoring of the particle concentration, the porous matrix symmetry and the composition. Furthermore, the existence of a "critical concentration limit" for embedding the particles within the body of the matrix has been confirmed. Exceeding the limit results in the expulsion of nanoparticles on the outer surface of the mesoporous matrix. Revelation of the relationships between particle concentration, matrix symmetry and magnetic properties of the particular composite reported in this study may facilitate the design and construction of advanced intelligent nanodevices.
采用湿浸渍法制备了嵌入介孔二氧化硅中的尺寸为7纳米和10纳米的精细FeO和GdO磁性纳米颗粒（NPs）。研究了反应物浓度以及主体基质对称性对纳米复合材料介观结构和磁性的影响。本研究使用了四种不同浓度的铁和钆离子反应物以及两种不同对称性（六方和立方）的二氧化硅基质。通过N吸附/解吸法、高能X射线衍射（HE-XRD）、TG/DTA和高分辨率透射电子显微镜（HRTEM）对样品进行了结构表征。通过超导量子干涉仪磁力计检测了纳米复合材料的磁性。研究发现，通过合理调整颗粒浓度、多孔基质对称性和组成，可以诱导出一系列不同的磁态（抗磁性、顺磁性、铁磁性、超顺磁性）。此外，还证实了在基质体内嵌入颗粒存在“临界浓度极限”。超过该极限会导致纳米颗粒被排斥在介孔基质的外表面。本研究中报道的特定复合材料的颗粒浓度、基质对称性和磁性之间关系的揭示，可能有助于先进智能纳米器件的设计和构建。
