TY  - GEN
ID  - heidok22246
Y1  - 2016///
KW  - Standard-Tunnelmodell
KW  -  Dielectric Function
KW  -  Standard Tunneling Model
KW  -  Nuclear Electric Quadrupole
KW  -  Relaxation
KW  -  Low Temperature Physics
KW  -  Amorphous Solids
KW  -  Glass
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/22246/
AV  - public
A1  - Luck, Annina
N2  - The measurements performed in this thesis have revealed a non phononic relaxation channel for atomic tunneling systems in glasses at very low temperatures due to the presence of nuclear electric quadrupoles. Dielectric measurements on the multicomponent glasses N-KZFS11 and HY-1, containing ¹?¹Ta and ¹??Ho, respectively, that both carry very large nuclear electric quadrupole moments, show a relaxation rate in the kilohertz range, that is constant for temperatures exceeding the nuclear quadrupole splitting of the relevant isotopes. The results are compared to measurements performed on the glasses Herasil and N-BK7 that both contain no large nuclear quadrupole moments. Using three different setups to measure the complex dielectric function, the measurements cover almost eight orders of magnitude in frequency from 60 Hz to 1 GHz and temperatures down to 7.5 mK. This has allowed us a detailed study of the novel effects observed within this thesis and has led to a simplified model explaining the effects of nuclear electric quadrupoles on the behavior of glasses at low temperatures. Numeric calculations based on this model are compared to the measured data.
TI  - Nuclear Spin dominated Relaxation of Atomic Tunneling Systems in Glasses
ER  -