摘要/索引

Magnetostructural correlations in cylindrite-based materials

Salyer, Pamela A.   The University of Texas at El Paso ProQuest Dissertations Publishing,  1999. 9959918.

摘要 (概要)

The mineral cylindrite (nominal composition FePb3Sn4 Sb2S14) is a layered chalcogenide with an unusual cylindrical morphology that occupies an important role in the search for new magnetic materials. The primary aim of this project is to characterize the magnetic properties of cylindrite, and to use the characterization to understand its structural and compositional variances. Due to its inherent curvature and incommensurate sublattices, the structure of cylindrite has historically proven difficult to solve, and the exact atomic positions are unknown. This work capitalizes on cylindrite's Fe content as a unique opportunity to further understand its structure and composition through magnetism. Magnetic investigations (both powder and single crystal) have been carried out on four separate specimens of cylindrite. The magnetic ion is confirmed as a six-coordinate, Fe +2, d6 ion with a high spin (S = 2) ground state of t2g 4eg2. Temperature dependent susceptibility (χ vs. T) studies reveal differences in magnetic behavior that can be attributed to cylinder aspect ratio (i.e., length/diameter = 2−10). Notably, a correlation between the cylinder aspect ratio and the magnetic anisotropy below 60 K is attributed to the chemistry of Fe+2 in cylindrite's lattice. A scheme invoking crystallographic relationships similar in concept to anti-ferrodistortive ordering enables the single-ion anisotropies (χ// and χ) for the Fe+2 ions in cylindrite to be deduced from the calculated average magnetic susceptibility (χavg). The magnetic studies, in combination with compositional analyses (i.e., Energy-Dispersive Spectrometry (EDS), Wavelength-Dispersive Spectrometry (WDS)) have led to several magnetostructural correlations and the proposal of a magnetic model for cylindrite-based structures.

索引(详情)


主题
Materials science
分类
0794: Materials science
标识符/关键字
Applied sciences; Cylindrite; Magnetostructural
标题
Magnetostructural correlations in cylindrite-based materials
作者
Salyer, Pamela A.
页数
342
学位日期
1999
学校代码
0459
来源
DAI-B 61/02, Dissertation Abstracts International
出版地
Ann Arbor
出版物国家/地区
United States
ISBN
978-0-599-63228-8
导师
Haar, Leonard W. ter
大学/单位
The University of Texas at El Paso
大学位置
United States -- Texas
学位
Ph.D.
来源类型
学位论文
语言
英语
文档类型
Dissertation/Thesis
学位论文/毕业论文编号
9959918
ProQuest 文档 ID
304549962
版权
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
https://www.proquest.com/unauthdocview/304549962