Micromagnetics of Nano-structures

小型磁性结构正在被开发用于磁性传感器（例如，利用巨磁阻效应，或隧道磁阻）对于利用霍尔效应或磁输运效应的非易失性存储器和纳米级存储器，它们在设计上提出了挑战，以提高开关场的值和再现性。温度效应以及介观尺度上晶粒结构的波动变得重要。在目前，IBM-Siemans正在开发磁性非易失性存储器（Infinion）和Motorola公司。开关场的均匀性是高密度非易失性磁存储器的主要障碍。目前可寻址位置的产量非常小。几乎所有当前的微磁学计算都是在零温度下进行的，并且不包括温度效应。此外，我们提出研究和开发一种方法来预测器件的特性，并利用我们在过去几年中开发的技术进行优化设计，这些技术包括：（a）从分析的角度结合我们编写和优化的有限温度Monte Carlo程序进行计算;（B）实验研究我们内部电子束图案化亚微米结构的开关场特性。

Small magnetic structures are being developed formagnetic sensors (for example, exploiting thegiant magnetoresistance effect, or tunneling magnetoresistance)for nonvolatile memories exploiting either the Hall effect or magnetotransporteffects and for storage on a nano scale.They present challenges in design for controllingthe value and reproducibility of the switching field.Temperature effects as well as fluctuationof the grain structure on a mesoscopic scale become important.At the moment, magnetic nonvolatile memories are being developed byIBM-Siemans (Infinion) and the Motorola Companies.The uniformity of the switching field is a major stumbling block in thecommercilaiztaion of high density nonvolatile magnetic memories.At the moment the yield of addressable sites is very small.Nearly all current micromagnetics calculations are carried outat zero temperature and do not include the temperature effects.In addition, very few systematic investigation were carried out.We propose to study and develop a way to predict the devicecharacteristics and enable their optimum designwith techniques that we have developed over the last several years.These include (a) calculations from an analytic point of view incombination with a finite temperature Monte Carlo code that we have written andoptimized; (b) experimental studies of the switching fieldcharacteristics of our in-house e-beam patterned submicronstructures.