Measurement of spontaneous magnetic fluctuations
- 1 January 1987
- journal article
- Published by EDP Sciences in Revue de Physique Appliquée
- Vol. 22 (5) , 367-374
- https://doi.org/10.1051/rphysap:01987002205036700
Abstract
We describe the first experimental system used to observe the thermal magnetic fluctuations in a magnetic system at equilibrium. We develop the calculation of the coupling of spontaneous magnetic fluctuations to a measuring system, emphasizing the difference with the classical case of susceptibility measurements. We report the power spectrum of the two spin glasses CdCr1.7In 0.3S4 and CsNiFeF6 which exhibit a 1/f dependence in the range 10-2 Hz to 102 Hz. Comparison between this observation and conventional a.c. susceptibility experiments in the same range of frequency supports the applicability of the fluctuation-dissipation theorem for CsNiFeF6Keywords
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