"The crystallographic and magnetic properties of the LaNi5-xFex (1≤ x≤ 1.4) and LaNi5-xMn5 (x = 0, 1, 1.5, and 2) compounds have been studied by x-ray and neutron diffraction, SQUID and Mössbauer spectroscopy (LaNi5-xFex only). All of the samples crystallized in the hexagonal CaCu5-type structure with space group P6/mmm. Both Fe and Mn atoms preferentially occupy the 3g site in these compounds. The LaNi5-xFex samples exhibit ferromagnetic properties for x ≥ 1.2. The different magnetic behavior observed in LaNi4Fe suggests the coexistence of both short and long range magnetic ordering. The magnetic structure of LaNi5-xMn5 for x = 1.5 and 2 is described by a ferrimagnetic model. A ferromagnetic model gives the best fit of the neutron diffraction data for LaNi4Mn. Calculations of the nearest-neighbor environments suggest that the difference between the magnetic structures of LaNi5-xMn5 is due to the Mn dilution.
The electronic structures of the LaNi5-xFex compounds with x = 1 and 2 have been modeled by the orthogonalized linear combination of atomic orbitals (OLCAO) method. Calculations of magnetic moments, total energy, which is related to the preference of Fe occupying the 3g site, and total density of states are consistent with the results from SQUID measurements, neutron diffraction data, and Mössbauer spectroscopy. The spin-polarized photoemission measurements did not provide quality data due to a sample magnetization problem caused by the low remanence of the samples. Spin-independent photoemission spectra for YCo5, NdCo5, and LaNi3.65Fe1.355 are presented"--Abstract, page iv.
Pringle, Oran Allan
James, William Joseph
Waddill, George Daniel
Marasinghe, Gaya K.
Parris, Paul Ernest, 1954-
Switzer, Jay A., 1950-
Ph. D. in Physics
University of Missouri--Rolla
Journal article titles appearing in thesis/dissertation
- Magnetic and Crystallographic Properties of LaNi5.xFex
The Crystal and Magnetic Structures of LaNi5-xMnx
- Electronic Structure Studies of Several Rare Earth-Transition Metal Compounds
xiv, 125 pages
© 2000 Chiu-Ying Tai, All rights reserved.
Dissertation - Restricted Access
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Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.http://merlin.lib.umsystem.edu/record=b4514972~S5
Tai, Chiu-Ying, "The magnetic and electronic structures of several rare earth-transition metal intermetallic compounds" (2000). Doctoral Dissertations. 1368.
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