Zn-Ti取代的BaFe12O19铁氧体

采用标准陶瓷工艺,并进行湿压磁场成型和氧气氛烧结制备了高取向度、低介电损耗的各向异性Ｂａ（ＺｎＴｉ）ｘＦｅ１２－２ｘＯ１９多晶六角铁氧体,随着ｘ值增大,磁化强度减小,居里温度下降,磁晶各向异性常数减小。结果可以通过假设Ｚｎ＾２＋取代了四面体４ｆ１次点阵位和六面体２ｂ次点阵位上的ＦｅＴ＾３＋;Ｔｉ＾４＋取代了自旋向上的八面体１２ｋ,２ａ次点阵位上的Ｆｅ６３＋来解释。     

Al^3＋和Mn^2＋对YGdCaVInIG性能的影响

本文对少含稀土氧化物的ＹＧｄＣａＶＩｎＩＧ材料的性能和结构进行了分析研究，重点讨论了用Ａｌ＾３＋和Ｍｎ＾２＋替代Ｆｅ＾３＋对铁氧体性能的影响。     

ZnxFe3—xO4的制备及性能

采用合适加剂在碱性溶液中制备了ＦｅＺｎ铁氧体，研究了其形成机理及磁性能，提出ＦｅＺｎ铁氧体的形成机理为：Ａｎ＾２＋＋２Ｆｅ＾３＋＋８０Ｈ＾－→ＺｎＦｅ２Ｏ４＋４Ｈ２Ｏ Ｆｅ＾２＋＋２Ｆｅ＾２＋＋８０Ｈ＾－→Ｆｅ３Ｏ４＋４Ｈ２Ｏ。     

K2NbOf5—MF3系玻璃的结构及电性质

研制了Ｋ２ＮｂＯＦ５－ＭＦ３（Ｍ＝Ａｌ、Ｇａ）新体系氟化物玻璃，测定了玻璃的特征温度、Ｒａｍａｎ光谱和电导率，玻璃中Ｎｂ＾５＋、Ａｌ＾３＋、Ｇａ＾３＋分别以ＮｂＯＦ＾２５、ＡｌＦ３＾５、ＧａＦ３６八面体形式存在，玻璃的电导率随ＡｌＦ３含量的增加而增加，当ＡｌＦ２含量达到３０ｍｏｌ％时，Ａｌ＾３＋除ＡｌＦ＾３６八面体外，还有ＡｌＦ４四面体结构出现，同时电导率降低，Ｆ阴离子是主要的导电离子，７５Ｋ２Ｎ     

某些氟化物的升华提纯

ＡｌＦ２在１１００℃升华时，因其蒸汽压和过滤金属氟化物杂质相近，升华分离比较困难，本工作采用较快速度升温和移动凝华区的办法，能满意地把带红棕色的ＦｅＦ３、ＣｕＦ２等杂质分离，得到含铁量〈１ｐｐｍ的无色ＡｌＦ３晶体。对ＢａＦ２、ＬａＦ３等高沸点氟化物原料，在１３５０℃升华时，能有效地除去过渡金属氟化物杂质。在氟化物玻璃中，存在Ｆｅ＾２＋Ｆｅ＾３＋的平衡，其中Ｆｅ＾３＋，其中Ｆｅ＾３＋从可见区到近红外     

（BiAl）YIG薄膜的生长感生磁各向异性

从理论和实验上分析了Ｆｅ＾３＋和Ｆｅ＾２＋对（ＢｉＡ）ＹＩＧ薄膜的生长感各向异性的贡献，掺Ｂｉ导致的生长磁感生各向异性，来源于Ｅｉ＾３＋改变了Ｆｅ＾３＋的零场劈裂，其大小取决于Ｂｉ＾３＋含量及在十二面体位的择优分布，高价离子和氧空位形成的Ｆｅ＾２＋在八面体位的择优分布，对生长感生磁各向异性也有贡献。     

镍内电极多层陶瓷电容器介质材料的研究

通过（ＢａＯ＋ＣａＯ）／（ＴｉＯ２＋ＺｒＯ２）略大于１的Ｂａ－ＴｉＯ３系材料进行受主离子Ｃａ＾２＋、Ｍｇ＾２＋、Ｆｅ＾３＋、Ｍｎ＾２＋和Ｚｎ＾２＋掺杂试验,使瓷料在还原性气氛中与镍电极共烧,获得介电常数为１５０００、绝缘电阻率达到１０＾１２Ω．ｃｍ的抗还原陶瓷。     

P204与C5—7羟肟酸液膜体系自湿法冶锌系统中同步迁移分别回收镓 …

提出了乳状液膜体系自湿法冶锌系统中经一级同时分离镓和锗的新方法,建立了用Ｐ２０４和Ｃ５－７羟肟酸协同载体,ｐＨ＝３．２的ＮＨ４Ｆ溶液为内水相试剂,使Ｇｅ＾４＋以溶液状态而Ｇａ＾３＋则以Ｇａ（ＯＨ）３沉淀同步迁移进入内水相并分别回收的液膜体系,研究了影响Ｇａ＾３＋、Ｇｅ＾４＋迁移的各种因素,经正交实验确定了分离镓和锗的最佳液膜组成及操作条件,并用加入铁粉法除去了杂质Ｆｅ＾３＋和Ｃｕ＾２＋对Ｇａ＾３＋     

缓蚀剂BMAT对不锈钢在5%盐酸中（含Fe^3＋）的缓蚀作用

用失重法及通过测定极化曲线，研究了５％ＨＣｌ中Ｆｅ＾３＋腐蚀的影响。结果表明，Ｆｅ＾３＋能改变不锈钢的阴极反应过程，当其含量超过１．５ｍｍｏｌ／Ｌ后，３１６Ｌ的腐蚀速度随着Ｆｅ＾３＋浓度的增大而增大。溶液中加入ＢＭＡＴ后，对Ｆｅ＾３＋的去有化过程有明显的抑制作用，且缓蚀剂的用量需根据Ｆｅ＾３＋的浓度来调整，ＢＭＡＴ的使用量为３ｍｍｏｌ／Ｌ时，酸洗液中Ｆｅ＾３＋的浓度应小于１．５ｍｍｏｌ／Ｌ。     

氟化物中Eu^2＋,Ce^3＋的浓度猝灭及其机理

本文详细地研究了ＢａＹＦ５和ＫＣａＦ３基质中Ｅｕ＾２＋、Ｃｅ＾３＋浓度对其发光的影响，发现两基质中Ｅｕ＾２＋、Ｃｅ＾３＋的猝灭浓度都较低；提出了Ｅｕ＾２＋、Ｃｅ＾３＋的浓度猝灭机理，计算了猝灭浓度和临界距离，并与实验结果进行了比较。     

Ti^4+掺杂M型六角铁氧体BaFe12–xTixO19陶瓷的磁学和介电特性

六角铁氧体由于其具备高温下的低场磁电耦合特性,有望应用于新型多态存储器及磁电传感器等微电子器件。利用Ti^4+离子对M型六角铁氧体BaFe12O19进行B位掺杂,不仅可以调控材料的磁结构和磁学特性,同时,Ti离子在六角铁氧体B位的不等价掺杂还可以产生相关缺陷、载流子和变价Fe离子进而改变其电学特性。本研究采用固相烧结法制备了M型六角铁氧体BaFe12–xTixO19(x=0,0.5,1,1.5)陶瓷,并对其进行了性能表征和测试,研究了B位Ti^4+掺杂对材料结构、磁学和介电特性的影响。研究结果表明,BaFe12–xTixO19呈现上、下自旋反平行的亚铁磁序。当Ti^4+离子掺杂量较低时,更易取代位于上自旋格子的Fe3+离子,其磁化强度随Ti掺杂量的增加而减小;随着Ti4+离子掺杂量的进一步增加,位于下自旋格子的Fe^3+离子也会逐渐被取代,此时,饱和磁化强度随掺杂量的增加而增加。此外,Ti^4+离子的引入也会使晶粒内部呈现半导性,在晶粒/晶界处产生Maxwell-Wagner界面极化,故而M型六角铁氧体BaFe12–xTixO19陶瓷会出现明显的低频介电增强并伴随着Maxwell-Wagner介电弛豫。     

Optically stimulated luminescence from Al2O3:C irradiated with relativistic heavy ions.

Optically stimulated luminescence (OSL) from Al2O3:C (ALOC) irradiated with selected heavy ions (4He, 12C, 40Ar, and 56Fe) was examined for discussion on the effectiveness of ALOC for space radiation protection dosimetry. The OSL efficiency on the absorbed dose basis was almost unity for He (LETinfinity x H2O: 2.2 keV x microm(-1)) and decreased with increasing LET for C (14 keV x microm(-1)), Ar (91 keV x microm(-1)), and Fe (198 keV x microm(-1)); a notable reduction greater than 60%, was observed for Fe ions. The linearity in dose response and the angular independence for the heavy ions were fairly good (+/- <15%) Although further experimental studies are clearly necessary, these results suggest that small ALOC chips can be a part of an integrating dosimetry system in future space missions.     

Effect of Non-magnetic Ions Substitution on Structural,Magnetic and Optical Properties of BiFeO3 Nanoparticles

Non-magnetic Zr⁴⁺ ions substituted BiFeO₃ nanoparticles (BiFe_1?x Zr _x O ₃, x = 0.0, 0.03 and 0.10) were synthesized by sol-gel method. X-ray diffraction and Raman studies indicate the rhombohedral phase for all the samples. The particle size decreases with increasing Zr⁴⁺ concentration and varies in the range 20–50 nm. The absorption spectra show the strong absorption of visible light with optical band gap variation 2.27–2.21 eV for pure and Zr-doped BFO nanoparticles. A large saturation magnetization value of 9.33 emu/g is observed for x = 0.03 sample. The reduction in saturation magnetization for x = 0.10 sample is attributed to the dominant role of an increasing number of non-magnetically active Zr⁴⁺ ions, and the formation of Fe–O–Zr coordination with increasing Zr⁴⁺ ions concentration becomes less magnetic sublattice.     

Activity and leaching features of zinc-aluminum ferrites in catalytic wet oxidation of phenol

A series of ZnFe(2-x)Al(x)O(4) spinel type catalysts prepared by sol-gel method have been characterized and tested for catalytic wet oxidation (CWO) of phenol with pure oxygen. The iron species existed in these materials as aggregated iron oxide clusters and Fe3+ species in octahedral sites. With a decrease in iron content the concentration of the first iron species decreased and the latter increased. Complete phenol conversions and high chemical oxygen demand (COD) removals were obtained for all catalysts during phenol degradation at mild reaction conditions (160 degrees C and 1.0 MPa of oxygen pressure). Increasing with the concentration of Fe3+ species in octahedral sites, induction period became significantly shortened. After phenol was completely degraded, the concomitant recycling of the leaching Fe3+ ions back to the catalyst surface was observed, and in this case it is possible to perform successful CWO reactions with some cycles. It is also suggested that during the reaction the Fe3+ cations coordinated in octahedral sites in the ZnFe(2-x)Al(x)O(4) catalysts are resistant to acid leaching, but the reduced Fe2+ cations become much more labile, leading to increased Fe leaching.     

Structural and Magnetic Properties of Sm$_3$(Fe$_1-rm x$Co$_rm x$)$_27.7$Ti$_1.3$

The structure and magnetic properties of Sm₃(Fe_1-x Co_x)_27.7Ti_1.3 compounds, with x ranging from 0 to 0.4, have been investigated by means of X-ray powder diffraction and magnetic measurements. The main phase formed was that of Nd₃(Fe, Ti)₂₉-type structure (3:29) with a relatively small amount of the ThMn₁₂-type structure (1:12) as a secondary phase (7-13 wt.%). The lattice parameters and the unit-cell volume decrease with increasing Co content x. It is found that substitution of Co for Fe leads to a significant increase in the Curie temperature from 488 K for x=0 to 941 K for x=0.4. Saturation magnetization gradually increases with increasing Co. All compounds show easy cone-type anisotropy     

Iron doped hexagonal ErMnO3: structural, magnetic, and dielectric properties

The single phase ErFe(x)Mn1-xO3 (0 < or = x < or = 0.15) compounds were synthesized by the solid-state reaction method. The doping effects on the crystal structural, magnetic, thermal, and dielectric properties were systematically investigated. The XRD patterns show all samples crystallize in the hexagonal structure with P6(3)cm space group. The lattice parameters a and c first decrease with doping, which is followed by a subsequent increase at higher doping levels. Although both the Fe3+ and Mn3+ ions remain stable in high spin trivalent states in all samples, the magnetization is weakened with increasing Fe contents. The heat capacity data shows the antiferromagnetic transition slightly shifts from 77 K for ErMnO3 to 80 K for ErFe015Mn0.85O3, which can not be observed in the magnetic susceptibility data. The real part of complex impedance of these samples rises as the doping level increases, indicating the enhancement of insulativity of doped samples.     

EPR Study of Borax-glasses with Addition of Fe~(3+) Ions

Glasses of xFe2O3 (l-x) Na2B4O7 for 0.3≤x≤5 mol% have been studied by means of EPR. The distribution of Fe3+ ions in the vitreous network. as isolated and connected in clusters. depends on the impurity contents in the glass. A thermal treatment inducing the Fe3+ -rich phase separation ends at the sample crystallization, when performed at about 550℃, Weathering of glasses causes a Superficial alteration of their optical properties. It enters the bulk of the glass for powdered samples. As a result of gamma irradiation pararnagnetic hole centers were detected:the BOHC. the peroxy radical and the iron hole centers     

Electron beam annealing of Fe+ implanted Si nanostructures

Silicon nanostructures (nanowhiskers) have been formed at surface densities approximately 10(9) cm-2 by electron beam annealing (EBA) prior to the implantation of 7 keV Fe+ ions to fluences from 1 x 10(13) - 4 x 10(15) Fe+ cm(-2). A second EBA step is then applied to relieve implantation-induced stresses. RBS analysis shows that the implanted Fe remains close to the surface. AFM characterisations of the implanted nanowhiskers before and after the final EBA step are summarised in graphs of height versus surface density. In a striking result it is shown that the nanowhiskers not only survive processing but also grow significantly. For example, at the highest fluence of 4 x 10(15) Fe+ cm(-2), the average height more than doubles: the increases are from 5.0 nm to 6.5 nm under implantation and from 6.5 nm to 11.8 nm under EBA. In addition there is a significant increase in surface density from an initial value of 1.6 x 10(9) cm(-2) to 4.3 x 10(9) cm(-2). These results highlight the feasibility of doping Si surface nanostructures with magnetic ions to fabricate Si devices for spin-dependent enhanced field emission.     

高温固相合成Ni_xZn_(1-x)Fe_2O_4铁氧体及物相组成分析

以Fe2O3、ZnO和NiO为原料,采用高温固相法合成NixZn1-xFe2O4(x=0～0.9)铁氧体,用差热分析、X射线衍射等测试技术对样品进行分析研究。结果表明:各产物中没有发现单一相的NiO、ZnO和Fe2O3存在,各产物均属立方晶系尖晶石结构且结晶完整。随着Ni的摩尔分数x的增加,衍射峰逐渐向高角度偏移,根据晶面间距公式计算可知,随着Ni摩尔分数x的增加,样品晶体晶胞参数逐渐减小,均是由于Zn2+、Fe3+和Ni2+3种金属离子大小与相对含量的变化引起的。