Co100-xMnx合金在GaAs(001)表面的生长结构和磁性的实验研究

对Co_100-xMn_x合金在GaAs(001)表面的分子束外延生长、晶体结构和磁学性质进行了研究.结果表明,当0100-xMn_x合金薄膜是体材料中不存在的体心立方(bcc)结构,并且具有较强的铁磁性,当44100-xMn_x合金薄膜最初为bcc结构,随着厚度的增加,逐渐从bcc向面心立方(fcc)结构转化,最后成为完全的fcc结构,薄膜具有较 关键词：     

Co1-xMnx合金电子结构和磁性的理论研究

Ｃｏ１－ ｘ Ｍｎｘ 合金的磁性强烈地依赖于其结构以及Ｍｎ 的相对含量．从第一性原理出发,用线性缀加平面波（ＬＡＰＷ） 方法,分别计算了ｘ ＝ ０００ ,０２５ ,０５０ ,０７５ ,１００ 的情况下,面心立方（ｆｃｃ） 和体心立方（ｂｃｃ） 结构的Ｃｏ１－ ｘ Ｍｎ ｘ 合金的电子结构和基态磁性．随ｘ 的增大,ｆｃｃ 结构的Ｃｏ１－ ｘＭｎ ｘ 合金的磁性从铁磁性和亚铁磁性变为反铁磁性;ｂｃｃ 结构Ｃｏ１－ ｘ Ｍｎｘ 合金从铁磁性减弱到亚铁磁性．较好地解释了有关Ｃｏ１ － ｘ Ｍｎ ｘ 合金的结构和磁性关联的实验结果     

磁场增强的La2/3 Sr1/3 MnO3有机半导体界面载流子注入

文章作者制备了以多种π-共轭有机半导体（orgnanic semincondutor,简称OSEC）为中间层,La2/3Sr1/3MnO3（LSMO）和另一铁磁或非磁性金属为电极的有机二极管,测量了器件的磁致电阻和磁电致发光效应.器件显示了与LSMO电极类似的负磁电阻效应,但是它的电阻变化比LSMO电极本身的变化大3个数量级,而且器件还有正的磁电致发光效应.文章作者认为,这些磁场效应源于磁场作用下LSMO费米能级的异常移动,导致载流子在LSMO-OSEC界面注入的增强。     

HT-7UPF导体的设计及其稳定性分析

使用简单地功率和能量平衡关系,分析了CICC(Cable-in-Conduit-Conductor)型超导体的稳定性。为了导体的设计,推导出一些仅含有超导电缆几何因子和导体运行参数的表达式。最后给了一种HT-7U极向场PF(Poloidalfield)线圈导体的设计结果。     

The basis of organic spintronics：Fabrication of organic spin valves

Organic spintronics focuses on utilizing the spin degree of freedom in organic materials because of the long spin relaxation time. The vertical organic spin valve (OSV) is a typical sample structure used to study the spin transport phenomena. However, the fabrication of high quality OSVs is difficult, which results in controversial experiment results and hence hinders the development of organic spintronics. In this work, we describe our recent study on the fabrication of typical vertical organic spin valves, La_0.67Sr_0.33MnO₃ (LSMO)/Alq₃/Co. The LSMO bottom electrodes are annealed to obtain an atomically smooth surface and improved magnetic properties. The top Co electrodes are deposited by an indirect deposition method to reduce the interfusion between Co and Alq3. The controlled fabrication process provides much better performance and sample yield of OSVs.     

The basis of organic spintronics： Fabrication of organic spin valvesl

Organic spintronics focuses on utilizing the spin degree of freedom in organic materials because of the long spin relaxation time. The vertical organic spin valve （OSV） is a typical sample structure used to study the spin transport phe- nomena. However, the fabrication of high quality OSVs is difficult, which results in controversial experiment results and hence hinders the development of organic spintronics. In this work, we describe our recent study on the fabrication of typical vertical organic spin valves, Lao.67Sro.33MnO3 （LSMO）/Alq3/Co. The LSMO bottom electrodes are annealed to obtain an atomically smooth surface and improved magnetic properties. The top Co electrodes are deposited by an indirect deposition method to reduce the interfusion between Co and Alq3. The controlled fabrication process provides much better performance and sample yield of OSVs.     

含四硫富瓦烯羧酸配体和二价金属钴离子一维链配合物的合成、结构和物理性质研究

本文以一种水溶性的冠醚环化四硫富瓦烯羧酸为配体,成功合成并表征了结构新颖的含四硫富瓦烯衍生物的二价钴一维配位聚合物[{Co2（trioTTF）2（H2O）6}·5H2O]n（1）.X射线单晶衍射结构分析表明,在配位聚合物1中Co^2＋离子之间通过羧酸桥联形成一维链状结构,相邻链的四硫富瓦烯羧酸配体之间存在较短的S…S相互作用.尽管配位聚合物1的室温电导率很小,但其电阻-温度特性曲线显示具有半导体性质.同时,磁性研究表明,低温下由羧酸桥联的Co2＋离子存在弱的铁磁相互作用.本研究为分子磁性半导体的进一步设计合成提供了思路.     

共沉淀法制备Co掺杂ZnO的室温铁磁性的研究

利用共沉淀法并在5vol.%H₂/Ar气流中于300 ℃退火3 h,制备了Zn_1-xCo_xO稀磁半导体. 扫描电子微探针分析表明,对Co的名义组分分别为0.05,0.10,0.15的样品,其实际组分分别为x＝0.054, 0.100和0.159. X射线衍射表明, 主相为纤锌矿结构, x=0.100和 0.159的样品中含有CoO杂相. X射线光电子谱显示出Co有３种状态: 替代进入Z 关键词： 稀磁半导体 ZnO 共沉淀法 磁性来源     

Co1-xMnx合金电子结构和磁性的理论研究

Co_1-xMn_x合金的磁性强烈地依赖于其结构以及Mn的相对含量.从第一性原理出发,用线性缀加平面波(LAPW)方法,分别计算了x=0.00,0.25,0.50,0.75,1.00的情况下,面心立方(fcc)和体心立方(bcc)结构的Co_1-xMn_x合金的电子结构和基态磁性.随x的增大,fcc结构的Co_1-xMn_x合金的磁性从铁磁性和亚铁磁性变为反铁磁性;bcc结构Co相似文献   

From self-assembly to quantum guiding: A review of magnetic atomic structures on noble metal surfaces

Recent advances in the study of magnetic atomic structures on noble metal surfaces are reviewed. These include one- dimensional strings, two-dimensional hexagonal superlattices, and novel structures stabilized by quantum guiding. The combined techniques of low-temperature scanning tunneling microscopy, kinetic Monte Carlo simulations, and ab initio calculations reveal that surface-state-mediated adatom-step and adatom-adatom interactions are the driving forces for self- assembly of these structures. The formation conditions are further discussed by comparing various experimental systems and the kinetic Monte Carlo simulations. Using scanning tunneling spectroscopy and tight-binding calculations together, we reveal that the spectra of these well-ordered structures have characteristic peaks induced by electronic scattering processes of the atoms within the local environment. Moreover, it is demonstrated that quantum confinement by means of nano-size corrals has significant influence on adatom diffusion and self-assembly, leading to a quantum-guided self-assembly.