| Autor: |
J. Smidt, D.J. Ligthelm, R.A. Wind |
| Rok vydání: |
1980 |
| Předmět: |
|
| Zdroj: |
Physica B+C. 100:175-190 |
| ISSN: |
0378-4363 |
| DOI: |
10.1016/0378-4363(80)90004-2 |
| Popis: |
Experimentally the Zeeman relaxation as a function of temperature, caused by the motions of the methyl groups in Ge(CH3)4 shows a “tunnelling” extreme and strongly non-exponential relaxation for ω0/2π = 38 MHz at 103/T = 23. 8 K−1 (T = 42 K) and forω0/2π = 73 MHz/T = 23.5 K−1 (T = 42.6 K). For ω0/2π= 9 MHz this tunnelling maximum and the strongly non-exponential relaxation are absent. The results were interpreted by means of the Symmetry Restricted Spin Diffusion model of Emid, Wind e.a. The effective tunnelling frequency ωt/2π and the correlation time τc, which both are a function of temperature were deduced from the experiments. By inserting these parameters in the S.R.S.D. relaxation equations good agreement between theory and experiment was achieved. The tunnelling maxima and strongly non-exponential relaxation for ω0/2π = 38 resp. 73 MHz were due to the conditions ωt = 2ω0 resp. ωt = ω0 and ω0τc ⪢ 1. The absence of this maximum and of strongly non-exponent ial relaxation for ω0/2π = 9 MHz are due to the fact that for this frequency these conditions could not be fulfilled simultaneously. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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