Date of Award

2000

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Advisor

Roy G. Goodrich

Abstract

To our knowledge the research reported here represents the first attempt to understand the 4f electronic structure in CeB6 using EPR. We report extensive temperature and angular dependent EPR measurements on a single crystal of CeB6 in the paramagnetic phase from 4 to 300 K at 35, 95, and a few measurements at 220 GHz. The 35 GHz measurements were performed at LSU and the 95 and 220 GHz measurements were performed at the National High Magnetic Field Laboratory, Tallahassee, FL. These experiments were made using a standard microwave frequency-locked spectrometer and magnetic field modulation. The measurements are supplemented by temperature and field dependent DC measurements of the sample magnetization. From the EPR line shapes, g-value and spin-lattice relaxation time (T1) were extracted. The EPR results for CeB6 showed one absorption peak at the magnetic field corresponding to temperature independent g-value of g = 1.98 and T1 = 6.35*10 -11 seconds at room temperature. The g factor for this transition is independent of temperature between 4 and 300 K, depends on magnetic field (measurement frequency) in a non-monotonic manner, and depends slightly on crystal orientation with respect to the applied field direction in the [100] plane. The line width of the EPR spectra decreased and the relaxation time increased with increasing temperature because of exchange narrowing. Similar measurements were performed on ferromagnetic EuB6 and g values and spin-lattice relaxation times were extracted.

ISBN

9780493071633

Pages

119

DOI

10.31390/gradschool_disstheses.7393

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