高磁光性能CexY3-xFe5O12多晶体的制备及磁学性能

Preparation and Magnetic Properties of CexY3-xFe5O12 Polycrystal with High Magneto-Optical Properties

摘要:

采用优化的溶胶-凝胶法制备了Ce³⁺掺杂的石榴石型Ce_xY_3-xFe₅O₁₂(x=0，0.1，0.2，0.3；Ce:YIG)多晶体，通过预烧处理和900~1400 ℃宽温度范围烧结获得无衍生杂质和高磁光性能的晶体。首先用热重分析确定了该晶体的合成温度为890 ℃。XRD结果表明该晶体的晶格常数在1.237 241~1.241 210 nm之间变化，当x>0.2时出现杂质相CeO₂。SEM分析表明，Ce:YIG的晶粒尺寸随着烧结温度和Ce³⁺ 含量的增加而增加，其尺寸分布范围为0.257~6.52 μm，该粒度值是目前获得的YIG晶体粒度的最大值。所有Ce:YIG样品在室温下呈现亚铁磁性，饱和磁化强度（M_s）在23.47~28.10 (A·m²)·kg^–1范围内变化。经过1200~1300 ℃烧结的Ce_0.1Y_2.9Fe₅O₁₂晶体的磁导率高达3.68~3.90。根据法拉第旋转角与磁导率的关系可知，该温度范围烧结的多晶体有可能获得最佳的法拉第旋转性能。

Abstract:

The garnet type polycrystal Ce_xY_3-xFe₅O₁₂ doped with Ce³⁺ was prepared by an optimized sol-gel method (x=0, 0.1, 0.2, 0.3; Ce:YIG). Crystals with no derived impurities and high magneto-optical properties prepared by pre-sintering and sintering in a wide temperature range of 900–1400 ℃ were obtained. Thermogravimetric analysis was used to determine the the crystal synthesis temperature of 890 ℃. XRD results show that the crystal lattice constant varies from 1.237 241 nm to 1.241 210 nm, and the impurity phase CeO₂ appears when x>0.2. SEM analysis shows that the grain size of Ce:YIG increases with the increase in sintering temperature and Ce³⁺ content, and its size distribution ranges from 0.257 to 6.52 μm, which is the maximum size of YIG crystal obtained at present. All Ce:YIG samples were ferromagnetic at room temperature, with saturation magnetization varying from 23.47 to 28.10 (A·m²)·kg^–1. The permeability of Ce_0.1Y_2.9Fe₅O₁₂ crystal sintered at 1200–1300 ℃ is as high as 3.68–3.90. According to the relationship between Faraday rotation angle and permeability, the polycrystal sintered in this temperature range is likely to obtain the best Faraday rotation performance.