In Situ Domain Structure Observation and Giant Magnetoelectric Coupling for PMN-PT/Terfenol-D Multiferroic Composites

摘要

In situ observations of ferroelectric domain structure evolution, and magnetoelectric (ME) coupling are investigated for PMN-28PT/Terfenol-D (abbreviation of Pb(Mg_(1/3)Nb_(2/3))O_3-28Pb TiO_3/Tb_(0.3)Dy_(0.7)Fe_2) and PMN-33PT/Terfenol-D composites under the magnetic loadings. The composite of PMN-33PT/ Terfenol-D shows stronger ME coupling than that in PMN-28PT/Terfenol-D. At a thickness of 0.10-0.12 mm for the single crystal plate, a giant magnetoelectric coefficient (α_(ME)) up to 2 V/cm·Oe is obtained for PMN-33PT/Terfenol-D at a static magnetic field of 200 Oe and 1 kHz of the alternating magnetic field. In situ domain structure observations reveal the domain morphology change during the applied magnetic loadings. In PMN-28PT, the domains are of predominantly rhom-bohedral (R) phase and they change into monoclinic M_A phase upon the magnetic loading via the strain transferred between Terfenol-D plate and PMN-PT single crystal. In PMN-33PT, domains of orthorhombic (O), R, and monoclinic M_C coexist and phase transitions from O to M_C and further to R phase occur upon the magnetic loading. The undulation and diversity of the domain structure makes the domains more susceptible to the magnetic loading via strain transferred between Terfenol-D plate and PMN-PT single crystal, and consequently, a strong ME coupling in the composites.