Study on magnetic role of Bi3+ ion by random cation distribution model in Bi–YIG system

Bi‐YIG system: The effect of cation relocation on structural, hyperfine, and magnetic properties

“…It is expected that at high levels of Bi substitution the saturation magnetization reaches a constant variation, even though in some works saturation magnetization is reported to fluctuate at high level of bismuth substitution . This ambiguity of saturation magnetization behavior motivated us to investigate the variation of saturation magnetization at high levels of Bi substitution.…”

Role of Ce concentration on the structural and magnetic properties of functional magnetic oxide particles

“…It is observed that the saturation magnetization ( M s ) decreases from 26.316 emu g −1 to 14.999 emu g −1 with the increase of Ce concentration. The behaviour of saturation magnetization can be explained by Neel's theory, 93,94 which claims that super-exchange interaction renders the magnetic moments of “a” and “d” sites in antiparallel positions. Here, Fe 3+ sublattices are antiferromagnetically coupled to the R 3+ ( i.e.…”

“…Also, the agglomerations increases because of different composition and their presence may be depends upon magnetic interaction and the chemical reaction during sintering process at a particular temperature which manifests better alignment between the grains [92]. behaviour of saturation magnetization can be explained by Neel's theory [93][94], which claims that super-exchange interaction renders the magnetic moments of "a" and "d" site in antiparallel positions. Here, Fe 3+ sublattices are antiferromagnetically coupled to the R 3+ (i.e.…”

“…Here, Fe 3+ sublattices are antiferromagnetically coupled to the R 3+ (i.e. Y 3+ , Ce 3+ and Bi 3+ ) sublattices [93][94][95][96]. As a result, the net magnetic moment can be written as eq.…”

Microstructure and Properties of Bi-doped Yttrium Iron Garnet Magneto-optical Ceramics Prepared by Hot-pressing Sintering Process

“…Key words: yttrium iron garnet; magneto-optical ceramics; Bi-doped; infrared transmittance; Faraday rotation 法拉第效应是磁光材料重要磁光特性之一, 表 现为当磁场作用于磁光材料时, 线性偏振光以平行 于磁场方向通过磁光材料后, 偏振平面发生旋转, 旋转方向仅与磁场方向有关, 与光的传播方向无关, 旋转角度大小与材料厚度及磁场强度有关。磁光材 料应用其法拉第效应可制备光隔离器 [1] 、相位调制 器 [2] 、偏振控制器 [3] 和数据存储器 [4] 等器件。YIG 材 料 [5] 在饱和外磁场下法拉第旋转角大, 且红外透过 率高、光吸收率低, 是制作法拉第旋转器(Faraday Rotator, FR)、红外光隔离器(Isolator)等器件的重要 核心材料。目前已应用的主要为 YIG 单晶材料, 通 常采用助熔剂法 [6] 、流动溶剂浮区(Traveling Solvent Floating Zone, TSFZ)法 [7] 、光学浮区法 [8] 等方法制备, 例如上海应用技术大学徐家跃等 [9] 以 PbO-B 2 O 3 为 助熔剂成功生长出高透过率 YIG 单晶。中国科学院 上海硅酸盐研究所武安华等 [10] 采用光学浮区法成 功制备了具有优异磁光性能的 Ce 掺杂的 YIG 晶体。 YIG 非一致熔融性的特点, 单晶制备难以获得大体 积块材, 限制了其应用。2018 年日本 Ikesue 等 [11] 首次通过氧气氛无压和 O 2 -Ar 气氛热等静压两步烧 结法获得磁光性能优良的高透过率 YIG 磁光陶瓷, 该报道预示采用陶瓷工艺有望获得组成精确可控、 磁光性能优异、红外透过率高的大尺寸 YIG 材料。 优质的磁光材料需要以尽可能小的尺寸去获得 更大的法拉第旋转角, 即提高磁光材料的旋光率 (θ F )。立方 YIG 晶格属于空间群 Ia3d [12] , 由三个磁 性亚晶格组成, 分别为八面体位(a)、四面体位(d)和 十二面体位(c)亚晶格 [13] , 其中十二面体(c)亚晶格 被非磁性离子 Y 3+ 离子占据。前期已有研究通过离 子半径适配的异质离子取代 Y 3+ , 以增强 YIG 的磁 光性能, 如三价稀土离子 [14][15][16][17] 或 Bi 3+ 离子 [18][19] 等。 在 YIG 材料中, 当 Bi 3+ 离子部分取代 Y 3+ 离子时, 其 法拉第旋转角出现反向旋转, 随 Bi 3+ 掺杂量增加近 似线性变化 [20] 。文献 [21] [22][23] , 只 能 在 GGG (Gd 3 Ga 5 O 12 )基衬底材料上外延生长, 生长速 度慢、生产周期长、成本非常高。Ikesue [11] 在氧气 氛围下热等静压(Hot Isostatic Pressing, HIP)烧结红 于 Y 3+ 的半径(0.1019 nm) [25] , 大半径 Bi 3+ 离子通过…”