Sandu V, Nicolescu M S, Kuncser V, Popa S, Pasuk I, Ghica C, Sandu E
National Institute of Materials Physics-Bucharest, Magurele, Ilfov, 077125, Romania.
J Nanosci Nanotechnol. 2012 Jun;12(6):5043-50. doi: 10.1166/jnn.2012.4943.
We present the preparation, structural and magnetic properties of nanosized magnetite obtained by the crystallization of a series of Fe-containing borosilicate glasses. Several compositions with the ratio Fe2O3/SiO2 spanning from 0.37 to 0.67 were investigated as a function of two nucleators Cr2O3 and P2O5, respectively, and modifiers and intermediates (Al2O3 and MgO). Mössbauer spectroscopy revealed the degree, the type and the location of disorder induced by a specific composition and nucleators. In addition to magnetite, it was also revealed the presence of large amounts of Fe-rich paramagnetic phases. The magnetic response is analysed in relation with the amount of Fe ions which remain dispersed in the glassy matrix as noninteracting (paramagnetic) ions. We discuss the role of the nucleators on the disorder in both tetrahedral and octahedral sites of the magnetite.
我们展示了通过一系列含铁硼硅酸盐玻璃的晶化所获得的纳米级磁铁矿的制备、结构和磁性特性。研究了几种Fe₂O₃/SiO₂ 比例范围从0.37到0.67的组合物，它们分别作为两种成核剂Cr₂O₃和P₂O₅以及改性剂和中间体（Al₂O₃和MgO）的函数。穆斯堡尔光谱揭示了由特定组成和成核剂引起的无序程度、类型和位置。除了磁铁矿外，还发现存在大量富含铁的顺磁相。结合作为非相互作用（顺磁）离子保留在玻璃基质中的铁离子数量分析了磁响应。我们讨论了成核剂对磁铁矿四面体和八面体位点无序的作用。
