| Autor: |
Glen E. Everett, M. Tachiki, Peter K. Schwob |
| Rok vydání: |
1974 |
| Předmět: |
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| Zdroj: |
Physical Review B. 10:165-178 |
| ISSN: |
0556-2805 |
| DOI: |
10.1103/physrevb.10.165 |
| Popis: |
The standing-spin-wave absorption spectrum in this EuS films has been measured in the temperature interval 1.3-4.2 K. The dependence of the magnetization on temperature has been determined from the ferromagnetic-resonance field and compared with spin-wave theory. The results are well described by the exchange-parameter combination $\frac{({J}_{1}+{J}_{2})}{{k}_{B}}=(0.096\ifmmode\pm\else\textpm\fi{}0.003)$ K. The temperature dependence of the exchange stiffness parameter $D(T)$ has been calculated including the contribution of a nonzero internal field. The experimental results have been analyzed taking the surface boundary conditions into account and correcting for the temperature and field dependence of ${H}_{i}$. The results show that the apparent temperature dependence of $D(T)$ arises almost entirely from the surface-anisotropy energy. The small observed variation $\frac{\ensuremath{\Delta}D(T)}{{D}_{0}}$ has been analyzed yielding $\frac{{J}_{2}}{{J}_{1}}=\ensuremath{-}0.57\ifmmode\pm\else\textpm\fi{}0.05$. The results, expressed as $\frac{{J}_{1}}{{k}_{B}}=(0.214\ifmmode\pm\else\textpm\fi{}0.026)$ K, $\frac{{J}_{2}}{{k}_{B}}=\ensuremath{-}(0.122\ifmmode\pm\else\textpm\fi{}0.025)$ K are in essential agreement with the inelastic-neutron-scattering determination of Passel et al. but in marked disagreement with Swendsen's Green's-function theory and its application to the calculation of the ferromagnetic and paramagnetic Curie temperature. A comparison with other experimental determinations of ${J}_{1}$ and ${J}_{2}$ is made. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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