A ferromagnetic (FM) thin film deposited on a substrate of $\mathrm{Pb}\left({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}\right){\mathrm{O}}_3\text{−}{\mathrm{PbTiO}}_3$ (PMN-PT) is an appealing heterostructure for the electrical control of magnetism, which would enable nonvolatile memories with ultralow-power consumption. Reversible and electrically controlled morphological changes at the surface of PMN-PT suggest that the magnetoelectric effects are more complex than the commonly used “strain-mediated” description. Here we show that changes in substrate morphology intervene in magnetoelectric coupling as a key parameter interplaying with strain. Magnetic-sensitive microscopy techniques are used to study magnetoelectric coupling in Fe/PMN-PT at different length scales, and compare different substrate cuts. The observed rotation of the magnetic anisotropy is connected to the changes in morphology, and mapped in the crack pattern at the mesoscopic scale. Ferroelectric polarization switching induces a magnetic field-free rotation of the magnetic domains at micrometer scale, with a wide distribution of rotation angles. Our results show that the relationship between the rotation of the magnetic easy axis and the rotation of the in-plane component of the electric polarization is not straightforward, as well as the relationship between ferroelectric domains and crack pattern. The understanding and control of this phenomenon is crucial to develop functional devices based on FM/PMN-PT heterostructures.

中文翻译：

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Fe / PMN-PT多铁异质结构中形貌与磁电耦合的相互作用

铁磁（FM）薄膜沉积在 $\mathrm{铅含量}（{镁}_{\mathrm{1个}/3}{铌}_{2/3}）{\mathrm{Ø}}_3\text{-}{\mathrm{钛酸铅}}_3$（PMN-PT）是一种用于磁性电学控制的吸引人的异质结构，它将使非易失性存储器具有超低功耗。PMN-PT表面的可逆和电控形态变化表明，磁电效应比常用的“应变介导”描述更为复杂。在这里，我们表明，衬底形貌的变化干预了磁电耦合，将其作为与应变相互作用的关键参数。磁敏显微镜技术用于研究Fe / PMN-PT中不同长度尺度的磁电耦合，并比较不同的基片切割。观察到的磁各向异性的旋转与形态的变化有关，并映射在裂缝模式中在介观尺度上。铁电极化转换引起微米范围的磁畴无磁场旋转，旋转角分布宽。我们的结果表明，磁易轴的旋转与极化的平面内分量的旋转之间的关系并不直接，铁电畴与裂纹模式之间的关系也不是简单的。了解和控制这种现象对于开发基于FM / PMN-PT异质结构的功能器件至关重要。