论文标题
磁性纳米斑块中螺旋波的动力学：厚度和形状的影响
Dynamics of Spiral Spin Waves in Magnetic Nano-patches: Influence of Thickness and Shape
论文作者
论文摘要
我们探讨了具有变化的几何尺寸宽度比的螺旋形旋转波的动力学，并且它们的潜在用途是不需要或小偏置场的改进的自旋波发射器。数值结果表明，在圆形闭合状态下，可以在圆形和平方形元件中获得一定厚度，传播的螺旋波。在20 nm（薄）和80 nm（厚）样品上进行的VNA-FMR实验证实了两种类型的光谱，对应于不同和较厚元件的不同分散体。我们表明，对于较厚的膜，涡流区域充当大振幅螺旋波的来源，在其他模式上占主导地位。如果较薄的元素，这些模式受到严重抑制。对于斑块的不同形状，我们表明，丰富的密闭传播模式集合也可以激发，从而改变了最终的波前，并丰富了作为自旋波发射器的纳米点的潜力。我们从样品中偶极和交换能量平衡的角度的角度给出了强烈的螺旋模式的解释。
We explore the dynamics of spiral spin waves in Permalloy nano-elements with variable aspect ratio of geometric dimensions, and their potential use as improved spin wave emitters with no or little biasing field required. Numerical results show that above a certain thickness, propagating spiral waves can be obtained in circular and square shaped elements in a flux closure state. VNA-FMR experiments on 20 nm (thin) and 80 nm (thick) samples confirm two type of spectra corresponding to different dispersions for thinner and thicker elements. We show that, for the thicker films, the vortex core region acts as a source of large amplitude spiral spin waves, which dominate over other modes. In case of the thinner elements, these modes are critically damped. For different shapes of the patch, we show that a rich collection of confined propagating modes can also be excited, modifying the final wave front and enriching the potential of the nano-dot as a spin wave emitter. We give an explanation for the intense spiral modes from the perspective of a balance of dipolar and exchange energies in the sample.
