柔性磁致伸缩FeGa薄膜与多层膜的磁性与输运性质的应力调控研究

In recent years, flexible magnetic films and devices have exhibited the great promise for applications in sensors and information storages due to the mechanical deformability and low processing cost. When flexible magnetoelectronics applied in curved surfaces, due to the magnetostriction effect, mechanical stress produced by magnetic films bending and stretching can often change their magnetic and transport behaviors. Because of the inhomogeneous residual stress in flexible substrates, the influence of mechanical stress on magnetic and transport properties of flexible magnetic films has been found quite different from that of rigid magnetic films reported in previous researches. In this project, we propose to deposit onto bendable plastic and ultrathin metallic substrates magnetic films, antiferromagnet/ferromagnet exchange biased heterostructures, and giant magnetoresistance multilayers based on FeGa films with large magnetostriction. By means of bending or stretching the films to produce mechanical stresses, the effect of applied stress on magnetic and transport properties of magnetostrictive FeGa films and multilayers will be studied. Considering magnetic interaction energies, we try to develop magnetization reversal mechanisms to interpret the magnetic switching processes for FeGa films and multilayered structures under various stressed states and to clarify the effect of stress on magnetic and transport properties in flexible magnetic thin-film structures. Our investigation will contribute to design, fabrication, and application of flexible magnetoelectronics.

柔性磁性薄膜与器件以其独特的柔韧性、延展性、高效低成本制造工艺，在信息、传感等领域具有重要的应用前景。当柔性磁性薄膜与器件应用在非平面表面，产生弯曲、拉伸等形变时，薄膜受到来自衬底的应力，由于磁致伸缩等效应其磁电性质将发生显著变化。然而柔性衬底中的应力不均匀性，使得应力对柔性磁性薄膜磁电性质的调控有别于以往研究刚性薄膜所获得的规律。本项目拟在柔性、可弯曲的聚合物和超薄金属衬底上生长大磁致伸缩FeGa薄膜、以及基于FeGa薄膜的柔性铁磁/反铁磁交换偏置异质结、巨磁电阻多层膜；通过弯曲和拉伸衬底对薄膜施加应力，研究应力对柔性磁致伸缩薄膜与多层膜磁性与输运性质的调控规律；考虑磁相互作用能，建立反磁化机制模型，理解不同应力状态下FeGa 薄膜与多层膜的磁化翻转过程，掌握应力对柔性磁性薄膜与多层膜磁电性质的调控机制。本项目研究对于柔性磁电子器件的设计与制备、性能调控、实际应用有着重要的参考意义。

柔性磁性薄膜与器件以其独特的柔韧性、延展性、高效低成本制造工艺，在信息、传感等领域具有重要的应用前景。当柔性磁性薄膜与器件应用在非平面表面，处于不同弯曲、拉伸等形变状态时，薄膜受到来自于衬底的应力/应变，由于磁致伸缩等效应其磁电性质发生显著变化。研究不同应力状态下柔性磁性薄膜与多层膜的磁电性质，掌握应力对其磁电性质的调控规律，对于柔性磁电子器件的设计与制备、性能调控、实际应用有着重要的意义。本项目针对具有大磁致伸缩的FeGa合金，研究了具有不同应力磁各向异性的FeGa薄膜的静态与高频磁性，提出了一种利用预应变生长提高FeGa薄膜铁磁共振频率的方法。研究了外延FeGa薄膜与异质结的磁化翻转过程，掌握了倾斜溅射诱导单轴各向异性对外延薄膜磁化翻转的影响规律。研究了应力对柔性自旋阀磁电阻的调控规律，掌握了应力对具有不同磁致伸缩系数自由层的自旋阀结构的调控规律。研究了柔性褶皱结构FeGa薄膜的制备与磁各向异性，掌握了以PDMS为衬底制备具有褶皱形貌FeGa磁性薄膜以及控制磁各向异性的方法，制备了柔性褶皱结构的巨磁电阻自旋阀器件。以通讯作者发表论文13篇，申请国家发明专利1项，并获授权。