Date of Award

12-1982

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Supervisor

Professor J.E. Greedan

Abstract

The magnetic structures of LaTiO₃ and CeTiO₃ were determined by neutron diffraction. LaTiO₃ is a G-type antiferromagnet. The Ti³⁺ sublattice in CeTiO₃ displays G-type and possibly F-type ordering. The Ce³⁺ sublattice exhibits F-type and C-type components.

Solid solutions of the form La͓Y₁₋͓TiO₃ and La͓Gd₁₋͓TiO₃ were prepared. Magnetic measurements suggest a weakening of the antiferromagnetic Ti-O-Ti exchange as the Ti-O-Ti bond angle decreases from 157°(LaTiO₃). For sufficiently small bond angle, the Ti-Ti exchange becomes ferromagnetic. Crystal field calculations based on a localized Ti³⁺ 3d¹ electron have reproduced the general features of susceptibility data reported for La͓Y₁₋͓TiO₃ (x=0,.1,.2,.4,.7). This is in agreement with resistivity measurements undertaken on La.₁.₉TiO₃ and La.₂Y.₈TiO₃ which are characteristic of an activated transport mechanism.

Included in

Chemistry Commons

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