Non-Equilibrium Magnetic Relaxation in High Coercivity Nanostructures

世界范围内正在努力了解高矫顽力磁性介质中的高速开关过程，以便优化能够支持预计接近1 GHz的记录数据速率的材料。在这里，建议与介质制造商Seagate合作，从实验和理论上解决这一问题，并实现四个具体目标：a)利用光刻技术制造集成的微型传感器来检测M(T)。一个独特的快速开关将由两个加压火花隙串联而成，它将提供4000 Oe的场脉冲，上升沿时间约为0.1 ns。B)将在阿拉巴马州和希捷溅射具有2000-4000 Oe的矫顽力的薄膜，并对薄膜的磁性和结构进行彻底的表征。与模型的预测相比，材料的发展将由实验开关数据来指导。C)建立了一个微磁模型，其中的阻尼常数取决于离散化的细度。将使用一种快速多极子方法来实现静磁场的有效编译。D)：希捷将根据这项研究的预测准备新的原型媒体，并对录制性能进行分析，以确定优化的高频媒体产品。最后，将在研究生、本科生和中学各级开展教育研究一体化计划。

A world-wide effort is in progress to understand the high speed switching process in high coercivity magnetic media in order to optimize materials capable of supporting recording data rates projected to approach 1GHz. Here it is proposed to attack the problem in collaboration with Seagate, a media manufacturer, experimentally and theoretically with four specific objectives: a) An integrated microsensor will be fabricated photolithographically to detect M(t). A unique fast switch using two pressurized spark gaps in series will be built which should provide field pulses of 4000 Oe with rise times ~0.1 ns. b) Thin films with coercivities of 2000-4000 Oe will be sputtered both at Alabama and at Seagate, and thoroughly characterized magnetically and structurally. Material development will be guided by the experimental switching data, compared to the predictions of the model. c) A micromagnetic model will be developed in which the damping constant depends on the fineness of the discretization. A fast multipole method will be used to allow the efficient compilation of magnetostatic field. d): New prototype media based on the predictions of this study will be prepared at Seagate and recording performance analyzed to define an optimized high frequency media product. Finally, a program integrating research in education will be carried out at the graduate, undergraduate and middle-school levels.