磁矩电调控抑制隧道结磁传感器1/f噪声方法研究

Micro magnetic sensors with high performance have some important applications in national security areas, such as underwater target detection, geomagnetic mapping navigation, space environment surveillance, and etc. Our courtry is very weak in this area. Magnetic tunneling junctions are the ideal sensing elements for the micro magnetic sensors with high performance. However, 1/f noise is a severe limitation of low-frequency performance, and the existed noise suppression methods are unsatisfied in stability. In this project, we will present a solution for suppressing 1/f noise of MTJ magnetic sensors through alternating electric-field manipulation of magnetization of flux concentrators which leads to the modulation of detected magnetic field. This method has advantages of low power dissipation, simple structures, well stability and high modulation efficiency. With the investigations on the alternating electric manipulation of magnetization of flux concentrators with piezoelectric substrate, 1/f noise suppression mechanism with modulated magnetic field, the simulation, design, fabrication, and characterization of MTJ magnetic sensors, we can find out that the magnetism manipulation of piezoelectric and ferromagnetic compound structures under alternating electric field, the magnetic 1/f noise suppression mechanism in MTJs under alternating magnetic field, and the characteristics of PMN-PT/CoFeB interface. Finally, the MTJ magnetic sensors with electric-field manipulation of magnetization will be fabricated and the findings of this project will support the further development of MTJ magnetic sensors in theory and technology.

高性能微型磁传感器在水下目标探测、地磁匹配导航、空间环境监测等国家安全技术领域具有重要应用，但我国在此方面十分薄弱。磁隧道结（MTJ）是高性能微型磁传感器的理想敏感体，但1/f噪声严重制约了其低频性能，且现有噪声抑制方法存在稳定性不足等问题。本项目针对此问题，提出利用交变电场调控聚集器内部磁矩从而改变增益实现对被测磁场的调制来抑制MTJ磁传感器1/f噪声的解决方法，它具有功耗低、结构简单、稳定性好、调制效率高等优势。主要研究压电基聚集器磁矩的交变电调控机理、调制磁场下MTJ磁敏感体的1/f噪声抑制机理、新型MTJ磁传感器的仿真设计、制备工艺及表征测试等内容，揭示交变电场对压电/铁磁复合体的磁性调控规律和交变磁场作用下MTJ磁性1/f噪声的抑制机理，掌握PMN-PT/CoFeB界面结合特性，研制出磁矩电调控MTJ磁传感器样品，为MTJ磁传感器技术的进一步发展提供理论和技术支持。

本项目针对MTJ中的1/f噪声抑制问题，开展了压电基磁力线聚集器磁矩电调控的交流特性及机理、调制磁场下MTJ磁敏感体的1/f噪声抑制机理、压电基磁力线聚集器的仿真设计方法等研究，提出了基于铁电/铁磁复合结构的MTJ磁传感器1/f噪声方法，建立了一套针对调制结构优化设计的方法，解决了交变电场对压电/铁磁多层复合体的磁性调控规律、交变磁场作用下MTJ磁性1/f噪声的抑制机理、压电晶体（PMN-PT）与非晶磁性薄膜的界面结合特性等关键科学问题，为研制出新型MEMS/TMR集成磁传感器样机奠定了重要基础；发表高水平学术论文14篇，SCI论文9篇；申请发明专利8项，已授权3项；课题组培养了博士研究生3名，硕士研究生3名（全部按原方向继续攻读博士学位，其中1人赴英国曼彻斯特大学诺贝尔奖团队联合培养）；获全国仪器科学与医学工程博士生论坛（国务院学位办主办）一、二、三等奖各1人；2名研究生获湖南省研究生创新资助；1名成员入选了国家留学基金委“未来科学家”项目首批资助（全国49人之一）。项目取得的成果超出预期目标。