Date of Award

Fall 2012

Degree Type

Thesis

Degree Name

Master of Science (MSc)

Department

Chemistry

Supervisor

Yurij Mozharivskyj

Language

English

Committee Member

John Greedan

Abstract

Series of rare-earth intermetallic compounds were synthesized and studied.

The Gd4Ge3-xPnx (Pn = P, Sb, Bi; x = 0.5 - 3) series of compounds were synthesized to explore the stability of the non-existent Gd4Ge3 binary through partial Pn substitutions to increase valence electron concentrations. Electronic band structure calculations were performed to elucidate the relationships between the hypothetical "Gd4Ge3" and Gd5Ge4 binaries. All Gd4Ge3-xPnx phases order ferromagnetically with relatively high Curie temperatures of 234 to 356 K.

The Gd5Ge4-xPx phases were synthesized to explore the effects of both atomic size and valence electron concentration differences between Ge and P atoms. Partial substitution of P for Ge atoms occur on the interslab site, which causes the interslab distances to increase. In Gd5Ge4-xPx, only a small amount of P substitution (x = 0.25) is required to induce ferromagnetic ordering. The appearance of a Griffiths phase is also discussed.

The temperature dependence of the different RE2Fe17 (RE = Gd - Ho) phases was tracked by reciprocal space images generated from single crystal X-ray diffraction.

GdCo4B was synthesized by arcmelting and tri-arc techniques to confirm the presence of magnetostriction. Single crystal and powder X-ray diffraction, dilatometer and magnetic measurements were done.

McMaster University Library

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