RUI: Mossbauer and Magnetization studies of Fe(1-x)Co(x)Z (Z = Si, Ge, and Sn) and Synthesis of Carbon Based Fullerenes using Laser Ablation

非技术描述：来自NSF的资金将在三年的时间内支持本科生的几项研究。这些研究将探索合成和检测半金属的新方法。当载流子的电子是一个自旋方向时，一半金属是导体，但对于相反方向的电子是绝缘体。本研究将由用于基质辅助激光解吸电离（MALDI）技术的新基质的开发来辅助，以寻找以前未观察到的一些母阴离子。半金属有望在未来电子设备的发展中发挥重要作用。提出的新方法包括在惰性气氛中的受控冷凝室中使用激光汽化半金属成分。由于激光烧蚀已被证明是一种生成富勒烯、内源性金属富勒烯和类似笼化分子的有效技术，因此将在这种支持的帮助下进行新的笼化分子物种的研究。除了可能合成新材料外，这些研究还为物理和化学本科生提供了动手体验的机会，他们希望通过教学和研究的综合方法来提高学生对物理，化学和材料科学的兴趣。技术细节：在公认的Fe(1-x)Co(x)Si化合物中，有特定的x范围，该材料被认为是半金属。在这些化合物中，半金属丰度的出现伴随着铁磁性。激光汽化技术将用于合成半金属族Fe(1-x)Co(x)Z（其中Z = Si， Ge和Sn），目的是通过替换元素周期表中同一列的元素来探索Z位元素大小对该族性质的影响。Fe(1-x)Co(x)（Ge, Sn）化合物尚未被观察到。激光烧蚀技术将用于寻找已被计算为能量稳定的笼状分子，如C12B24N24。随着激光消融在加热区梯度中的升华技术将用于分离各种混合金属化合物，其中氮拉曼光谱和计算可用于结构测定。此外，还将研究各种基质，以观察氢化富勒烯的母阴离子。本科生将获得激光烧蚀和飞行时间质谱等新技术的实践经验。

NON-TECHNICAL DESCRIPTION: Funding from NSF will support several studies over a three year period in an undergraduate setting. These studies will explore new ways of synthesizing and examining half-metals. Half metals are conductors when the carrier electrons are one spin orientation, but are insulators to electrons of the opposite orientation. This research will be assisted by the development of new matrices to be used in the matrix assisted laser desorption ionization (MALDI) technique in search of some parent anions that have not been previously observed. Half-metals have shown promise to play an important role in the development of future electronic devices. The proposed new method involves the use of laser vaporization of the half-metal constituents in a controlled condensation chamber in an inert atmosphere. As laser ablation has proven to be an effective technique of generating fullerenes, endohedral metallofullerenes, and similar caged molecules, a search for new caged molecular species will be undertaken with the help of this support. In addition to the possible synthesis of new materials, these studies offer the opportunities of hands-on experience for physics and chemistry undergraduate students, which they hope will serve to increase the students' interest in physics, chemistry, and material science in an integrative approach of teaching and research.TECHNICAL DETAILS: In the well-established Fe(1-x)Co(x)Si compounds there are specific ranges of x for which the material is considered to be a half-metal. The appearance of half metallicity is accompanied by ferromagnetism in these compounds. The laser vaporization technique will be used to synthesize the family of half metals Fe(1-x)Co(x)Z (where Z = Si, Ge, and Sn) with the goal of exploring the effect of the size of the Z-site elements by substituting elements from the same column of the periodic table on the properties of this family. Fe(1-x)Co(x)(Ge, Sn) compounds have not yet been observed. The laser ablation technique will be utilized in search of caged molecules that have been calculated to be energetically stable such as C12B24N24. Sublimation techniques that accompany the laser ablation in a heated zone gradient will be used to separate the various mixed metal compounds where Raman spectroscopy under nitrogen and computations can be employed for structural determination at the University of Tennessee. Furthermore, various matrices will be investigated to observe the parent anions of hydrogenated fullerenes. Undergraduate students will have hands-on experience in new technologies such as laser ablation and time-of-flight mass spectrometry.