Weimin Peng

Publication Date

1990

Document Type

Dissertation/Thesis

First Advisor

Kimball, Clyde W.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Physics

LCSH

Copper oxide superconductors; Superconductivity; Yttrium

Abstract

It is shown that Fe substituents in the Cul site of YBa₂Cu₃₋ₓFeₓO₇₊[sub δ] (x =0.15, 0.30) magnetically order into quasi- ID chains with strong intrachain but weak interchain coupling. The strong fluctuation behavior expected in low dimensional systems above and below T[sub N] is observed via characteristic relaxation in the Mossbauer line width near T[sub N]. The temperature dependence of the magnetic subspectra representing Fe ions with various local oxygen environments are in agreement with a 2D-Ising model, with a ratio of the anisotropic exchange between the two directions of the order of 0.5-1 . 0 (10⁻³). The concentration dependence of the relative occurrence of various magnitudes of the local dopant magnetization is related to a short range chemical order which determines the magnetic chain size and defines the correlation lengths. Evidence is given that the presence of rare earth magnetic moments in the Y-site affects the character of the magnetic interaction in the Cul-site.

Comments

Includes bibliographical references (pages [45]-50)

Extent

50 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

Download

Share

COinS