The magneto-optical Faraday effect was used, to observe
the spin-bath relaxation in Europium doped CaF₂ crystals at
helium temperatures from 1.5 to 4.2° K. Theory shows that the
magnitude of the Faraday rotation is proportional to the
difference in population of the ground state doublet. The
experimental method used in this thesis is the same as that
which was successfully used by Glattli and by Griffiths. Pulsed
microwave power at X-band frequencies was employed to disturb
the equilibrium between the spin system and the bath.
The observed relaxation time t was expected to have a T⁻¹
temperature dependence hut because of the orientation of the
crystal in our dc magnetic field which resulted in the seven
transition lines being close together, cross-relaxation effects
produced a temperature dependence of approximately T⁻². It is
suggested that exchange coupled pairs of Eu²⁺ and clusters
involving Eu³⁺ may account for this temperature dependence
rather than there being a phonon bottleneck present.
The field dependence of the relaxation time was found not
to be directly related to the resonance spectrum,
The Eu²⁺ concentration of the crystals used in this thesis
was .2% / Science, Faculty of / Physics and Astronomy, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41715 |
| Date | January 1967 |
| Creators | Clarke, Thomas E. |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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