Non-stoichiometry and magneto-optic properties of magnetic bubble thin films of TmIG substituted with bismuth and gallium

Thulium iron garnet thin films substituted with bismuth and gallium were prepared by LPE from a PbO.B₂O₃ flux. Radioactive isotope tracers were added to the melt as the chemical analysis technique. The deviation from the ratio (Pb+Bi+Tm)/(Fe+Ga)=0.6 of the layers was large and a proportion of the thulium ions possibly lie on the octahedral crystallographic sites. The concentration of Bi, Pb, and Ga as a function of the growth temperature was studied. The magneto-optic properties show that the layers are well suited for use in a magneto-optic device. A figure of merit of 2.5 degree per decibel at λ=560 nm was obtained and some magnetic bubble parameters are also presented.     

The behavior of unintentional impurities in Ga0.47 In0.53As grown by MBE

A number of factors contribute to the high n-type background carrier concentration (high 10¹⁵ to low 10¹⁶ cm⁻³) measured in MBE Ga_0.47In_0.53As lattice-matched to InP. The results of this study indicate that the outdiffusion of impurities from InP substrates into GalnAs epitaxial layers can account for as much as two-thirds of the background carrier concentration and can reduce mobilities by as much as 40%. These impurities and/or defects can be gettered at the surfaces of the InP by heat treatment and then removed by polishing. The GalnAs epitaxial layers grown on the heat-treated substrates have significantly improved electrical properties. Hall and SIMS measurements indicate that both donors and acceptors outdiffuse into the epitaxial layers during growth resulting in heavily compensated layers with reduced mobilities. The dominant donor species was identified by SIMS as Si, and the dominant acceptors as Fe, Cr and Mn.     

Crystalline properties of multiple BP-Si layers grown on silicon substrate

In BP (100) epitaxially grown on Si (100), a high density of defects existed in the early growth layer of the BP less than 100 nm from the Si interface. The BP layer then had a uniform distribution of defects over the high density defect layer. The Si (100) grown on the BP (100) had a uniform distribution of defects. As multiple BP-Si layers were grown, the crystalline quality gradually degraded. The crystalline quality of the underlying BP layer strongly influenced the Si epitaxial layer.     

表面层型半导体陶瓷电容器

对表面层型半导体陶瓷电容器的基本结构原理、关键生产技术、关键设计参数、关键生产设备以及电容器规格和典型特性作了简要介绍。     

流速比对颗粒在液固两相平板混合层中沉降的影响

本文采用流动显示的方法对平板混合层中上下层流体速度比对固体颗粒在混合层中沉降的影响进行了研究。实验中分别采用粒径小于 ４０ ｕｍ,粒径 ９８～１０４ｕｍ,粒径 １５４～１６０ｕｍ的玻璃微珠以及环氧树脂作为固相颗粒,对这些颗粒在速度比分别为１：１．２、１：２和１：２．８的液相混合层中的运动进行了显示。结果表明混合层中大涡结构对固体颗粒的沉降具有迟滞作用,其作用程度取决于混合层中上下层流体速度比。速度比越大,颗粒的沉降越慢。     

石墨电极的纯度对直读光谱分析的影响

石墨电极的纯度对光谱分析的影响只是在一些书中提及,表作试验研究和分析,对电极的纯度的检验未作有效论述。文中就此问题提出了作者的见解,拟定了检验电极纯度的方法。     

微波强场中的光谱激发现象

本文报道了元素,化合物和放电灯在微波强场产生的激发现象。介绍了一种在微波强场中产生原子发射光谱的新方法。采用作者自行改制的微波激发装置,即可使固态的元素和化合物产生光谱辐射,也可使各种放电灯和气体光谱管得以激发,用一种装置实现了几种装置的功能,对于该方法存在的问题,文中也作了一定的说明。     

火焰原子吸收光谱法测定茶叶中的钾、钠、铷

本文报道了空气－乙炔火焰原子吸收光谱法测定茶叶中钾,钠,铷的含量。茶叶采用硝酸消解,方法简单,快速,回收率为９９．９％－１０５．２％,相对标准偏差为２．７８％－８．９６％。     

火焰原子吸收光谱法测定钙盐试剂中的痕量镉

采用巯基棉分离富集钙盐试剂中的前量镉,用火焰原子吸收光谱法进行测定。方法简便、快速,结果满意。样品测定的相对标准偏差均小于４．８１％。