Özetler/Ayrıntılar

Magnetostructural correlations in cylindrite-based materials

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

Özet

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.

Dizinleme (ayrıntılar)


Konu
Materials science
Sınıflandırma
0794: Materials science
Tanımlayıcı / anahtar kelime
Applied sciences; Cylindrite; Magnetostructural
Başlık
Magnetostructural correlations in cylindrite-based materials
Yazar adı
Salyer, Pamela A.
Sayfa sayısı
342
Derece tarihi
1999
Okul kodu
0459
Kaynak
DAI-B 61/02, Dissertation Abstracts International
Basım yeri
Ann Arbor
Yayınlanma ülkesi
United States
ISBN
978-0-599-63228-8
Danışman
Haar, Leonard W. ter
Üniversite/enstitü
The University of Texas at El Paso
Üniversite konumu
United States -- Texas
Derece
Ph.D.
Yayın türü
Bilimsel İnceleme veya Tez
Dil
İngilizce
Belge türü
Dissertation/Thesis
Bilimsel inceleme/tez numarası
9959918
ProQuest belge kimliği
304549962
Telif Hakkı
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
https://www.proquest.com/unauthdocview/304549962