铁磁共振磁交换力显微镜

Magnetic exchange force microscopy using ferromagnetic resonance

原子间的自旋相互作用力对原子级别磁性纳米构造体的表面磁性质的理解是极为重要的.磁交换力显微镜是测量表面自旋作用力的重要手段,但它的缺点一是需要加外部强磁场,二是不能分离表面形貌和自旋信息,这就导致材料表面受外部磁场的影响,而且表面形貌和自旋信息之间相互影响,使自旋间的相互作用力的检测和成像研究受到限制.为了解决上述问题,利用原子力显微镜,并采用微波照射的方法,根据铁磁共振原理,分别独立提取磁性材料表面形貌和自旋信息,称之为铁磁共振磁交换力显微镜,理论和实验结果表明此方法可以有效地分离两种信息.铁磁共振磁交换力显微镜可以促进对原子级磁性材料机能的理解以及磁性相关科学领域的进步,特别是对自旋电子元件的发展有很大的促进作用,是新世纪高度信息化社会不可缺少的测量技术.

Electron spin is very important for investigating magnetic properties of nano-structure surface on the atomic scale. Magnetic exchange force microscope （MExFM） which is a significant method of measuring exchange force of electron spin, is adopted. However, the external magnetic field is necessary for the MExFM, which will damage the structure of the sample surface; further, cross-talk between topography and spin information becomes serious for separating the two signals in MExFM measurement. These shortcomings will restrict the application of MExFM. In order to solve these problems, we develop a new method to separate the topography from the spin information using ferromagnetic resonance by microwave radiation combined MExFM and atomic force microscopy. We demonstrate that the topography and spin information can be completely separated from each other using this method theoretically and experimentally. MExFM using ferromagnetic resonance effect is very useful for developing spintronic devices and new-generation magnetic materials.