柔性铁电/铁磁复合结构中多重物理场对磁各向异性的调控研究

精确控制样品生长时的磁各向异性是实现性能可控的磁电子器件的基础，在此基础上，通过外场动态的调控磁各向异性进而控制磁电子器件的性能。由于衬底温度的影响，样品生长时的磁各向异性往往很难做到精确可控，此外，磁场控制的磁电子器件存在着结构复杂、体积大、功耗高的缺点，而单一的电场、应力场也很难实现对磁化方向的任意调控。实现样品生长时磁各向异性精确的调控及探索样品生长后磁化方向新的控制方式对于未来微型化、低功耗的磁电子器件来说具有重要意义。本项目拟选择柔性铁电PVDF作为衬底，制备磁致伸缩金属（合金），利用PVDF的柔性、大的各向异性热膨胀、铁电性，研究生长时施加的应力、温度、磁场对磁各向异性的调控规律；样品生长后，研究应力、温度、电场对磁各向异性的调控规律；利用多重物理场在三维空间的耦合实现对磁化方向的任意调控，获得最佳的柔性铁电/铁磁复合结构，为新型多重物理场控制的磁电子器件的应用打下基础。

Manipulation of the magnetic anisotropy accurately during the preparation lays the foundation for the control of the magnetic devices. After the preparation, external fields are used to tune the functionality of the magnetic devices. However, it is difficult to control the magnetic anisotropy accurately during the preparation because of the influences from the change of the temperature. On the other hand, Magnetic fields are used to tune the functionality of the magnetoelectric device, which is slow, bulky, and consumes excess energy, and electric-field or strain field itself is difficult to control the magnetization orientation arbitrarily. The accrate control of the magnetic anisotropy during preparation and manipulation of magnetization orientation by other means are needed intensely. In this project, flexible ferroelectric PVDF substrates will be chosen to prepare flexible ferroelectric/magnetostrictive metal (alloy) structure. By using the advantage of flexibility,anisotropic thermal expansion, ferroelectricity of PVDF, force, temperature and magnetic field will be applied during the preparation to control the magnetic anisotropy. After preparation, force, temperature, electirc-field will be coulped together to control the magnetic anisotropy. Based on the results, the model for the multi-field control of the magnetizaiton orientation will be built according to the coherent rotation and domain wall displacement theory. By optimizing the thickness, scale, dimensionality,shape, etc, we want to control the magnetization orientation arbitrarily by multi-field coupling and lay the foundation for the applications of the multi-flied controlled magnetic devices.