Preparation and Characterization of Transparent Magnetic Oxide Meterials

透明磁性氧化物材料是作为磁性装置和用于屏蔽磁性场的窗口使用的。当前研究的目标是准备新的透明磁性氧化物材料，并表征其最终材料的磁性、光学和磁性特性。研究的主要结果可以归结为如下：（1）法拉第效应测量已在减少大气层下准备好了一些苏打硼玻璃的室内温度。The Verdet constant is analyzed in terms of a theory derived by Van Vleck and Hebb to obtain effective transition for the 4 f ^7* 4 f ^6 5 d transition which canuses the Faraday effect of Eu^<2+> in the visible range。有效的过渡波长度随着玻璃光学基础的增加而增加。这一现象被解释为水晶场理论的术语;因为五个层次的分裂是更大的。 ... More n具有较大光学基础的玻璃，对4f^7*4f^6 5 d过渡退化的能量要求为玻璃增加的光学基础。当EuO保留常量的一致性时，Verdet恒定增加的幅度与有效过渡波的增加。（2）我们已经研究了热处理温度和时间对磁性属性的快速quenched氧化物的影响，如果我们发现的房间温度为60 ZnO·40 Fe_2O_3，则研究人员将注意力集中在氧化物与纳米化合物接近的情况下。X射线衍射、Zn K边缘扩展的X射线吸收精细结构（EXAFS）、Mossbauer光谱学和磁性测量已被装载到澄清晶体结构和磁性性能的变化与热处理。快速锁定的特定物质含有0.05%的晶格参数，小于ZnFe_2O_4的主要相位，并在房间温度中显示了23.8 emu/g的磁性。X-ray Diffraction、EXAFS和Mossbauer测量建议高磁性化是由Fe^<3+>离子簇与Zn^<2+>离子簇一起使用八度位点作为良好的Fe_3O_4固体溶液在ZnFe_2O_4中的Fe_2O_4。由于热处理温度增加，房间温度磁性衰减缓慢地低于500个C和降比600个C时，热处理时间为2小时。The variation of EXAFS and Mossbauer spectra with heat treatment temperature suggests that the decrease of magnetization below 500？C corresponds to the transfer of Zn^<2+> ions from Octahedral to tetrahedral sites while the rapid decrease of magnetization above 600？C is caused by the oxidation of Fe^<2+> to form ZnFe_2 O_4 with normal spinel structure。复杂的行为在550 ℃左右观察到;在550-600 ℃左右观察到磁化一次增加，然后迅速减少为热处理温度增加。我们设想，在Fe^<2+>氧化的初始阶段，以及Fe^<3+>的空缺，并导致在八个位点上创建磁性增加。Less（低）

Transparent magnetic oxide materials are useful as magnetooptical devices and windows for shielding of magnetic fields. The aim of the present research is to prepare new transparent magnetic oxide materials and to characterize the magnetic, optical, and magnetooptical properties of the resultant materials. The main results of the research can be summarized as follows :(1) Faraday effect measurements have been carried out at room temperature for some sodium borate glasses containing Eu^<2+> ions prepared under a reducing atmosphere. The wavelength dependence of the Verdet constant is analyzed in terms of a theory derived by Van Vleck and Hebb to obtain effective transition wavelength of the 4f^7*4f^6 5d transition which canuses the Faraday effect of Eu^<2+> in the visible range. The effective transition wavelength increases with an increase in the optical basicity of glass. This phenomenon is explained in terms of the crystal field theory ; because the splitting of 5d levels is larger i … More n the glass with larger optical basicity, the energy required for the 4f^7*4f^6 5d transition decreases as the optical basicity of glass increases. The magnitude of Verdet constant increases with an increase in the effective transition wavelength when the concentration of EuO remains constant.(2) We have examined the effect of heat treatment temperature and time on the magnetic properties of rapidly quenched oxides with compositions close to ZnFe_2O_4, which show high magnetization even at room temperature as we found. In particular, an attention is focused on the oxide with nominal composition of 60ZnO・40Fe_2O_3. X-ray diffraction, Zn K-edge extended X-ray absorption fine structure (EXAFS), Mossbauer spectroscopy, and magnetization measurements are carried out to clarify the variation of crystal structure and magnetic properties with heat treatment. The rapidly quenched specimen contains zinc ferrite with lattice parameter 0.05% smaller than that of ZnFe_2O_4 as the main phase, and exhibits the magnetization of 23.8 emu/g at room temperature. The X-ray diffraction, EXAFS and Mossbauer measurements suggest that the high magnetization is brought about by the Fe^<3+> ion clusters with the Zn^<2+> ions occupying octahedral sites as well as the solid solution of Fe_3O_4 in the ZnFe_2O_4. As the heat treatment temperature increases, the room temperature magnetization decreases sluggishly below 500ﾟC and decreases sharply above 600ﾟC when the heat treatment time is 2h. The variation of EXAFS and Mossbauer spectra with heat treatment temperature suggests that the decrease of magnetization below 500ﾟC corresponds to the transfer of Zn^<2+> ions from octahedral to tetrahedral sites while the rapid decrease of magnetization above 600ﾟC is caused by the oxidation of Fe^<2+> to form ZnFe_2O_4 with normal spinel structure. A complicated behavior is observed at around 550ﾟC ; the magnetization once increases at 550-600ﾟC and then decreases rapidly as the heat treatment temperature increases. We speculate that at the initial stage of the oxidation of Fe^<2+>, vacancies of Fe^<3+> ions at the octahedral sites are created, leading to the increase of magnetization. Less