界面磁电耦合诱导的磁性金属薄膜的可变形微波磁谱

This project aimed to break the fixed modes of magnetic spectra for a certain magnetic metallic thin film, and to make it be transformable. The key point is to tune interfacial interaction of ferromagnetic/ferroelectric system. The magnetic metallic thin film with different spin polarized ratio will be deposited by radio-frequency sputtering on substrate with large polarization. The fabrication technology will be adjusted base on the characterizations of structure, morphology and the magnetic and electric properties of the films. The interfacial magnetoelectric interaction will be tuned by changing the magnetization and polarization with external magnetic and electric field as well as temperature. The transformable magnetic spectra could be obtained on these ferromagnetic/ferroelectric system measured by ferromagnetic resonance and short circuited microstrip line. Combining with the spin rectification measurements, the possible nature of the transformable magnetic spectra will be discussed. Mode of the transformable magnetic spectra will be simulated with the Landau-Lifshitz-Gilbert equation and the Maxwell equations. The successful study of this project will not only find new response rule for the microwave, but also helpful for the design of new microwave functional devices.

本项目以突破同一磁性金属薄膜具有确定的微波磁谱形状这一现状，实现可变形的微波磁谱为目的。以调控铁磁/铁电的界面磁电耦合为关键，以磁性金属薄膜/高电极化强度基底为载体展开研究。拟用射频溅射技术在铁电或高介电常数基底上制备不同自旋极化率的磁性金属薄膜；结合结构和形貌观测以及基本物性表征，掌握不同厚度的磁性金属薄膜制备工艺。通过施加直流电场和磁场及改变温度，调整基底的电极化强度和薄膜的磁化强度，实现界面磁电耦合的调控。通过不同界面磁电耦合的铁磁共振和短路微带线测量，获得磁性金属薄膜的可变形微波磁谱。结合不同厚度和自旋极化率薄膜的整流电测量，探索界面磁电耦合诱导的磁性金属薄膜中可变形磁谱的本质；利用修正的Landau-Lifshitz-Gilbert方程和Maxwell方程的数值模拟探索微波磁谱变形的模式。该研究对于发现磁性金属薄膜材料的微波响应新规律，实现新的微波功能器件具有重要意义。

本项目以高电极化强度基底上生长的铁磁金属薄膜为载体，重点开展了磁电耦合诱导的可变型微波磁谱研究，突破了传统上人们对磁谱调控的认识。利用射频溅射和外延生长技术制备了不同自旋极化率的磁性金属薄膜，实现了决定磁谱共振位置的各向异性和磁化强度的控制。提出了剥离磁电耦合应力效应的铁磁共振和矢量网络磁谱方案，获得了磁化强度和电极化强度耦合的界面磁电耦合新效应。发现了磁谱变型的本质是界面磁电耦合导致的微波磁场相位变化，并证明了该相位变化来源于界面处自旋波诱导的自旋在铁磁金属薄膜中的扩散。该研究对于认识磁性金属薄膜材料的微波响应新规律，实现新的微波功能器件具有重要意义。同时，项目支持感兴趣的个别同学开展了能源材料的研究。本项目发表论文33篇，获批发明专利1件。培养4名博士生和3名硕士生。