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.
