Origin of hysteretic magnetoelastic behavior in magnetoelectric 2-2 composites

The local magnetization behavior of the magnetostrictive phase of ferromagnetic/piezoelectric magnetoelectric composites is compared to the hysteretic response using advanced magneto-optical imaging. Local magnetoelastic relaxation leads to the formation of magnetization modulated branched domain structures in the magnetic phase. This results in a complex field response governed by interlocking domain processes. An interrelation of magnetic domain formation and the piezomagnetic response is derived, revealing the origin of the hysteretic magnetoelectric response. As a result, domain wall induced effects lead to a reduction of magnetoelectric signal. Controlling the magnetic domain formation processes is the foundation for reversible magnetoelectric behavior.