论文标题
磁性纳米结构的测量和模拟自旋波模式光谱的比较
Comparison of measured and simulated spin-wave mode spectra of magnetic nanostructures
论文作者
论文摘要
由于纳米磁体中磁化动力学在磁性设备和传感器的开发和优化中的重要性，我们在图案化的椭圆形纳米磁体中测量并建模了自旋波光谱。通过使用杂质磁光微波显微镜测量了由电子束光刻制造的Ni80Fe20多种纳米磁性的铁磁共振光谱，其标称短轴为200 nm或100 nm。使用相同纳米磁体拍摄的扫描电子显微镜图像定义微磁模拟的元素形状。测得的光谱显示，名义上相同的纳米磁体之间存在显着差异，这只能部分归因于图案过程中不受控制的形状变化，这是通过测量和模拟光谱之间有限的一致性的证据。通过在模拟中纳米磁体的边缘上包括一个减少磁化和交换的区域，可以改善测量和模拟之间的一致性。我们的结果表明，单个磁随机访问记忆元素之间的形状变化减少可以潜在地提高其性能。但是，基于分析和自旋波谱建模的纳米磁体中材料参数的明确确定仍然有问题。
Motivated by the importance of magnetization dynamics in nanomagnets for the development and optimization of magnetic devices and sensors, we measured and modeled spin wave spectra in patterned elliptical nanomagnets. Ferromagnetic resonance spectra for multiple nanomagnets of Ni80Fe20 , fabricated by electron-beam lithography to have nominal short-axes of 200 nm or 100 nm, were measured by use of heterodyne magneto-optical microwave microscopy. Scanning electron microscope images taken of the same nanomagnets were used to define element shapes for micromagnetic simulations. Measured spectra show significant differences between nominally identical nanomagnets, which could be only partially attributed to uncontrolled shape variations in the patterning process, as evidence by the limited agreement between the measured and simulated spectra. Agreement between measurements and simulations was improved by including a zone of reduced magnetization and exchange at the edges of the nanomagnets in the simulations. Our results show that the reduction of shape variations between individual magnetic random-access memory elements can potentially improve their performance. However, unambiguous determination of materials parameters in nanomagnets based on analysis and modeling of spin wave spectra remains problematic.
