Goldstone-mode induced susceptibility-singularity extending toT
c
of the Heisenberg ferromagnet EuS |
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Authors: | J Kötzler D Görlitz R Dombrowski M Pieper |
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Institution: | (1) Institut für Angewandte Physik, Universität Hamburg, D-20355 Hamburg, Germany |
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Abstract: | At internal magnetic fields much smaller than the spontaneous magnetizationM
s
(T) but large compared to the weak anisotropy field,H
A
20 Oe, the internal susceptibility measured parallel toM by NMR and low frequency ac-susceptibility is observed to diverge asH
–1/2 for temperatures up to 0.998T
c
. Numerous theoretical work predicted suchH
–1/2-singularity to arise from massless Goldstone-modes associated with the perpendicular susceptibility of a Heisenberg system. The temperature variation of the amplitude,
z
·H
–1/2, agrees with the results of the spin-wave and more general hydrodynamic theories, while the magnitude reveals the suppression of one Goldstone polarization by the dipoledipole interaction. In contrast to a previous renormalization-group estimate, a crossover to thermal critical behavior nearT
c
is not observed. |
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Keywords: | 75 40 Cx 75 30 Ds 75 30 Kz 75 50 Dd |
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