Vibrating ferromagnets in a magnetic field

With the vibrating reed technique we have studied the magnetoelastic behavi or and the dynamical response of amorphous and crystalline magnets in the f erromagnetic and re-entrant spin glass states. The measurements have been p erformed as a function of magnetic held. temperature and angle between the sample's main area and the applied field. The resonance frequency of the re ed is influenced by a static contribution (pore effect), a dynamic contribu tion with a large effect due to the pinning of magnetic domains and magneto strictive effects. When the held is applied perpendicular to the main area of the sample, a large decrease of the resonance frequency is observed whic h is rather independent of the material characteristics and is not related to a change of the Young modulus. A field misalignment of a few degrees str ongly affects the field dependence of the resonance frequency. We briefly d iscuss the influence of the re-entrant spin glass state on the magnetoelast ic behavior and the characteristics of the internal friction of vibrating f erromagnets in a magnetic field. (C) 3000 Published by Elsevier Science S.A .