The magnetic and electronic structures of several rare earth-transition metal intermetallic compounds

Author

Chiu-Ying Tai

Abstract

"The crystallographic and magnetic properties of the LaNi_5-xFe_x (1≤ x≤ 1.4) and LaNi_5-xMn₅ (x = 0, 1, 1.5, and 2) compounds have been studied by x-ray and neutron diffraction, SQUID and Mössbauer spectroscopy (LaNi_5-xFe_x 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 LaNi_5-xFe_x 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 LaNi_5-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 LaNi_5-xMn₅ is due to the Mn dilution.

The electronic structures of the LaNi_5-xFe_x 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 LaNi_3.65Fe_1.355 are presented"--Abstract, page iv.

Advisor(s)

Pringle, Oran Allan
James, William Joseph

Committee Member(s)

Waddill, George Daniel
Marasinghe, Gaya K.
Parris, Paul Ernest, 1954-
Switzer, Jay A., 1950-

Department(s)

Physics

Degree Name

Ph. D. in Physics

Publisher

University of Missouri--Rolla

Publication Date

Summer 2000

Journal article titles appearing in thesis/dissertation

• Magnetic and Crystallographic Properties of LaNi_5.xFe_x

• The Crystal and Magnetic Structures of LaNi_5-xMn_x

• Electronic Structure Studies of Several Rare Earth-Transition Metal Compounds

Pagination

xiv, 125 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2000 Chiu-Ying Tai, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Thesis Number

T 7786

Print OCLC #

45965348

Recommended Citation

Tai, Chiu-Ying, "The magnetic and electronic structures of several rare earth-transition metal intermetallic compounds" (2000). Doctoral Dissertations. 1368.
https://scholarsmine.mst.edu/doctoral_dissertations/1368