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

Abstract

In situ observations of ferroelectric domain structure evolution, and magnetoelectric (ME) coupling are investigated for PMN‐28PT/Terfenol‐D (abbreviation of Pb(Mg1/3Nb2/3)O3‐28PbTiO3/Tb0.3Dy0.7Fe2) 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 (αME) 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 rhombohedral (R) phase and they change into monoclinic MA 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 MC coexist and phase transitions from O to MC 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.