Antidot and Ring Arrays for Magnetic Storage Applications

磁阵列存储技术应用的主要挑战是精确控制磁开关。为了实现这一点，需要具有可再现的剩余状态，其次，开关过程本身必须简单且可再现。只有在极少数具有明确的各向异性的情况下，反转才会通过磁化的相干旋转发生。然而，更常见的是，反转是通过元件末端的结构域形成发生的。对于任意形状的纳米尺度细长元件，一般不可能从基本原理可靠地计算出畴初形成的场。如果存储元件是环形而不是细长的，则磁通量在圆形模式下形成闭合，并且消除了与线性元件末端相关的问题。除了涡旋态外，环形元素还表现出两种不同的高度稳定的“洋葱”态。两种可能的洋葱状态，正向或反向磁化，可以实现剩磁和可用于磁存储。另一方面，磁性介质中的逆结构，即非磁性反点（与负点相同），可能是一种潜在的面密度接近750 Gb/in2的磁记录系统。PI提出了周期性反点阵列的系统实验研究，以与目前可用的理论预测进行比较。研究了解毒剂引起的磁性能变化、不同形状解毒剂的不同剩余状态、磁晶各向异性的影响、薄膜厚度以及高密度存储的可能应用，并研究了高密度极限的探索。

The major challenge in technological applications of magnetic arrays for storage is to control the magnetic switching precisely. To achieve this one needs to have reproducible remanent state and, second, the switching process itself must be simple and reproducible. Only in very few cases with well-defined anisotropies does the reversal take place via a coherent rotation of the magnetization. More common, however, is that the reversal occurs via the domain formation at the ends of the element. For arbitrary shape nano-scale elongated elements, in general, it has been impossible to reliably calculate the field at which domain first forms from basic principles. If the memory element is ring instead of elongated, the magnetization flux forms a closure in the circular mode and the problems associated with the ends of the linear elements are eliminated. The ring elements exhibit two different highly stable 'onion" states in addition to the vortex states. Two possible onion states, forward or reverse magnetized, can be realized at remanence and can be used for magnetic storage. On the other hand, it has been suggested that the inverse structure, nonmagnetic antidots (same as negative dots) in magnetic media, could be a potential system f or magnetic recording with areal densities approaching 750 Gb/in2. The PI proposes the systematic experimental study of periodic antidot arrays to compare with theoretical predictions presently available. The investigation of the changes in the magnetic properties induced by the antidotes, different remanent states for antidotes of various shapes, influence of magnetocrystalline anisotropy, film thickness and possible application for high-density storage will be performed and the exploration of the high-density limits will be studied.