应变诱导超低功耗自旋存储机理及实现研究

Based on spin torque effect to tune magentic moments, magnetic tunnel junctions (MTJs) use spin to record infomation. Since its high density, non-volatile and high thermal stability, this type of recording has become the key of the next generation random access memory. Following the demands for high recording density, this technology meets power and Joule-heating damaging problems, which limit its development. Recently, magnetoelectric multiferroic heterostructures, which can tune magnetic moments by strain, have become an important method to achieve ultra-low-power consumption tunable magnetic devices. Based on this new approach, our new proposal is planned to assist magnetic moment reversal in magnetic memory cell by strain. First, we plan to found a model by magnetoelectric mechanism to assist the memory layer to reverse. Based on this theoretical research, we will first fabricate CoFeB, CoFe magnetic layer on PMN-PT substrate. Then, the response of magnetoelectric induing, the way for high effeicency stain transfer and nonvolatile magnetization modulation will be researched. In the end, we will fabricate MTJ, and study the stain in the whole structure. Finally, we will research on finding an effect way to achieve ultra-low-power consumption and voltage-controlled magnetic memory.

基于电流自旋转矩效应驱动磁性薄膜磁矩翻转的磁隧道结，由于其高存储密度、非易失、高热稳定性，已成为新一代随机存储结构研究的核心。而随着集成系统对存储密度不断提升的要求，自旋转矩电流持续升高所带来的能耗、焦耳热损坏问题变得日益尖锐，已限制了其进一步发展。近年来，新型多铁异质结通过反磁电耦合效应，利用应变调制材料磁矩取向，已成为超低能耗可调磁性器件的重要实现途径。因此，本研究力图基于此，通过应变辅助存储单元磁矩翻转，实现电压调控下的低功耗磁存储。项目首先将基于多铁异质结磁电耦合机理，构建应变辅助隧道结存储层翻转模型并获取其实现条件；其次，利用PMN-PT等高应变基片，探索磁电耦合响应、应变高效传递、非易失应变辅助CoFeB、CoFe等存储层翻转的有效途径；最后，制备磁隧道结，研究应变层间传递对存储单元稳定性、一致性影响，实现压控辅助单元0、1信号存储，推进超低功耗非易失性磁存储的发展。

基于电流自旋转矩效应驱动磁性薄膜磁矩翻转的磁隧道结，由于其高存储密度、非易失、高热稳定性，已成为新一代随机存储结构研究的核心。而随着集成系统对存储密度不断提升的要求，自旋转矩电流持续升高所带来的能耗、焦耳热损坏问题变得日益尖锐，已限制了其进一步发展。近年来，新型多铁异质结通过反磁电耦合效应，利用应变调制材料磁矩取向，已成为超低能耗可调磁性器件的重要实现途径。因此，本研究首先基于多铁异质结磁电耦合机理，探索了应变辅助隧道结存储层翻转模型并获取了其实现条件。其次，基于CoFe、NiCo等常用自旋存储材料，探索了磁电耦合响应、应变高效传递、非易失应变辅助磁矩翻转的有效途径及对应变基片的依赖性；最后基于应变对磁性层的磁矩的有效调控，构建了基于磁单层、自旋阀及隧道结的超低功耗非易失性磁存储结构。基于本项目研究工作的开展，共发表研究论文10篇，SCI检索10篇，最高影响因子超10，申请国家发明专利9项，授权4项，很好的完成了项目的目标要求。