Antidot and Ring Arrays for Magnetic Storage Applications

存储用磁阵列在技术应用中的主要挑战是精确控制磁开关。为了实现这一点，一个需要具有可重复的剩余状态，第二，切换过程本身必须是简单和可重复的。只有在极少数各向异性明确的情况下，磁化强度的相干旋转才会发生反转。然而，更常见的是，反转是通过元件末端的磁区形成发生的。对于任意形状的纳米级细长元件，通常不可能根据基本原理可靠地计算出区域首先形成的场。如果存储元件是环形的而不是细长的，则磁化通量以圆形模式形成闭合，并且消除了与线性元件的端部相关的问题。除了涡旋态外，环元素还表现出两种不同的高度稳定的洋葱状态。两种可能的洋葱状态，正向磁化或反向磁化，可以在剩磁时实现，并可用于磁存储。另一方面，有人提出，磁性介质中的非磁性解毒剂(与负点相同)是一种潜在的磁记录系统，其面密度接近750 GB/in2。PI建议对周期性反点阵列进行系统的实验研究，以与目前可用的理论预测进行比较。将研究解毒剂引起的磁性变化，不同形状解毒剂的不同残留状态，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，并将研究高密度极限的探索。

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.