Date of Award

2001

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Advisor

Roy G. Goodrich

Abstract

The de Haas van Alphen (dHvA) effect, which measures the oscillatory component of the magnetization, in several CexLa1-x MIn5 (M = Rh, Co, Ir) alloys for 0 ≤ x ≤ 1 has been studied in detail using torque, pulse field and field modulation techniques. The frequencies, associated extremal cross sectional areas of the Fermi surface and effective masses of each sample throughout each of the series are reported. The energy band calculations of CeRhIn5, CeCoIn5 and CeIrIn5 assume that the 4f electrons in Ce are completely delocalized and these electrons make a significant contribution to the topology of the Fermi surface. It is observed that the band calculations are in agreement with the dHvA measurements for CexLa1-x CoIn5 and CexLa1-xIrIn5 . However, the dHvA measurements on CexLa1-xRhIn 5 show that the 4f electrons are entirely localized in CeRhIn5. The measurements show that the effective masses of carriers for each series vary slowly at low concentration and a dramatic increase is observed at high concentrations for B || [001]. In addition, for Co and Ir series at low concentrations (x ≤ 0.25), the mass enhancement agrees with the existing theory. The Dingle temperature measurements suggest that the replacement of La by Ce increases the scattering rate of the electrons for M = Co, Ir, not for M = Rh. For x = 0.5 and higher concentrations dHvA measurements on CexLa1-xRhIn5 show that dHvA oscillations originate from only one spin direction. However, dHvA measurements on Co and Ir series for x ≤ 0.10 show that there is no single spin dependence contributing to the oscillations.

ISBN

9780493562889

Pages

136

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