Preparation and Characterization of Transparent Magnetic Oxide Meterials

透明磁性氧化物材料的制备及表征

• 批准号: 06453122
• 负责人: SOGA Naohiro
• 金额: $ 5.38万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06453122/
• 关键词: glass; Faraday effect; Mossbauer effect; ferrite; rapidly quenching method; magnetization; crystal structure; 希土類; 酸化物ガラス; フッ化物ガラス; 配位子場; f-α遷移; ヴェルデ定数; 結晶化ガラス; マグネタイト; 微結晶; 磁気ポーリング; 磁気異方性; 保磁力; メスバウアー効果; 核生成

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

透明磁性氧化物材料可用作磁光器件和屏蔽磁场的窗口。本研究的目的是制备新的透明磁性氧化物材料，并对所得材料的磁、光和磁光性质进行表征。主要研究结果如下：(1)在还原气氛下制备了含Eu~(2+)、Lt；~(2+)和Gt~(2+)离子的钠硼玻璃，并在室温下进行了法拉第效应测量。根据Van Vleck和Hebb的理论分析了Verdet常数与波长的关系，得到了4f^7*4f^6 5d跃迁的有效跃迁波长，该跃迁导致Eu^&lt；2+&gt；在可见光范围内的法拉第效应。有效跃迁波长随玻璃光学碱度的增加而增大。用晶场理论解释了这一现象，因为i…的5d能级分裂较大。光学碱度越大的玻璃，4f^7*4f^6 5d跃迁所需的能量随着玻璃光学碱度的增加而减小。当EuO浓度不变时，Verdet常数的大小随着有效跃迁波长的增加而增大。(2)研究了热处理温度和时间对成分接近ZnFe_2O_4的快速淬火氧化物磁性的影响，发现即使在室温下也表现出较高的磁化强度。特别是对名义成分为60ZnO·40Fe_2O_3的氧化物进行了X射线衍射、锌K边扩展X射线吸收精细结构(EXAFS)、穆斯堡尔谱和磁化强度测量，阐明了热处理过程中晶体结构和磁性的变化。快淬态样品的主相为锌铁氧体，其晶胞参数比ZnFe2O4小0.05%，室温磁化强度为23.8emu/g。X射线衍射、EXAFS和穆斯堡尔谱分析表明，高磁化强度是由Fe~(2+)&lt；2+&gt；离子团簇占据八面体位置以及Fe_3O_4固溶体形成的。随着热处理温度的升高，室温磁化强度在500ﾟC以下缓慢下降，在600ﾟC以上急剧下降。EXAFS和穆斯堡尔谱随热处理温度的变化表明，低于500ﾟC的磁化强度的下降对应于锌离子从八面体向四面体的转移，而高于600ﾟC的磁化强度的快速下降是由于Fe^&lt；2+&gt；氧化生成具有正常尖晶石结构的锌铁氧体所致。在550ﾟC附近观察到一个复杂的行为；磁化强度在550-600ﾟC时一度增加，然后随着热处理温度的升高而迅速下降。我们推测，在Fe~(2+)和Gt~(2+)氧化的初始阶段，在八面体位置产生了Fe~(2+)和~(2+)&Gt~(2+)离子的空位，从而导致磁化强度的增加。较少

项目成果

Katsuhisa Tanaka: "Precipitation of magnetite from yttrium iron silicate glass" Journal of Materials Science Letters. 14. 370-372 (1995)

Katsuhisa Tanaka：“从钇铁硅酸盐玻璃中沉淀磁铁矿”材料科学快报杂志。

Kazuyuki Hirao: "Preparation and optical properties of transparent glass-ceramics containing B-PbF_2:Tm^<3+>" Journal of Applied Physics. 78. 3445-3450 (1995)

Kazuyuki Hirao：“含 B-PbF_2:Tm^<3> 的透明玻璃陶瓷的制备及其光学性能”应用物理学杂志。

Katsuhisa Tanaka, Yoh Nakahara, Kazuyuki Hirao and Naohiro Soga: "Preparation and Magnetic Properties of Glass-Ceramics Containing Magnetite Microcrystals in Calcium Iron Aluminoborate System" Journal of Magnetism and Magnetic Materials. (in press). 167

Katsuhisa Tanaka、Yoh Nakahara、Kazuyuki Hirao 和 Naohiro Soga：“铝硼酸钙铁体系中含有磁铁矿微晶的玻璃陶瓷的制备和磁性”杂志《磁性与磁性材料》。

Katsuhisa Tanaka: "Mossbauer spectra of binary iron oxide based glasses at liquid nitrogen temperature" Physics and Chemistry of Glasses. 36. 244-246 (1995)

Katsuhisa Tanaka：“液氮温度下二元氧化铁基玻璃的穆斯堡尔光谱”《玻璃物理与化学》。

Katsuhisa Tanaka et al.: "Preparation and magnetic properties of glass-ceramics containing magnetite microcrystals in calcium iron aluminoborate system" Journal of Magnetism and Magnetic Materials. (印刷予定). (1997)

Katsuhisa Tanaka 等人：“铝硼酸钙铁体系中含有磁铁矿微晶的玻璃陶瓷的制备和磁性”，《磁性与磁性材料杂志》（1997 年）。