| Autor: |
Vuorinen, R. T., Hakonen, P. J., Yao, W., Lounasmaa, O. V. |
| Zdroj: |
Journal of Low Temperature Physics; March 1995, Vol. 98 Issue: 5-6 p449-487, 39p |
| Abstrakt: |
We have measured the susceptibility of polycrystalline rhodium foils, down to nuclear spin temperaturesT = 280 pK and “up” toT = -750 pK. AtT > 0, the static susceptibility follows the antiferromagnetic Curie-Weiss law with ? = -1.8±0.3 nK. AtT < 0, the expected ferromagnetic behavior in the vicinity ofT = -0 changes into antiferromgnetic tendency around -6 nK. If only nearest and next nearest neighbor interactions are assumed, our data yieldJn/h = -17±3 Hz andJnnn/h = 10±3 Hz for the exchange interaction coefficients. We have also investigated the field and polarization dependence of the spin-lattice relaxation time t1 at positive and negative nanokelvin temperatures; surprisingly t1 is longer whenT< 0. Infields below 1 mT, the Korringa constant shows a strong decrease, which becomes more pronounced as the conduction electron temperature decreases. Observed behavior is consistent with conduction electrons scattering from magnetic impurities, provided that the impurity-induced contribution to spin-lattice relaxation is proportional to the inverse of the nuclear spin temperature in small fields. |
| Databáze: |
Supplemental Index |
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