Domain-Acoustic Echo with Long-Term Memory in Magnets

The stimulated domain-acoustic echo (DAE), possessing a long-term acoustic memory was
inductively excited by three RF pulses in a number of magnetostrictive and magnetoelectric materials
using a pulsed NMR technique with inductive and electric recording of DAE signals.
The study of the DAE intensity and magnetization dependence on the outer magnetic field showed
that the long-term memory of DAE is caused by the irreversible changes of magnetization in the
magnetostrictive and magnetoelectric materials related with displacements of domain walls or due to
the magnetostriction in magnetite powder grains at the interaction of the acoustic wave generated by
the first RF pulse with the magnetic field of the second RF pulse. The results of comparative study
DAE phenomenon in polycrystalline ferrite, europium garnet, iron borate and magnetoelectric layered
composite are presented.