Investigation of New Soft Magnetic Films for GHz Magnetic Recording Heads and Integrated Inductors

具有低矫顽力和高磁导率的软磁薄膜是许多电磁器件的重要组成部分，如磁记录磁头、集成电感器（微电感器）、集成变压器、磁传感器和微机械电机。然而，缺乏具有高饱和磁化强度（20kg）、高磁导率（1000）和高铁磁共振频率（1ghz）的软磁材料，往往是这些应用的瓶颈。例如，到2003年，硬盘驱动器的数据速率预计将达到~ 1gb /s （1gb = 10亿比特）。2gb /s的数据速率对应的记录频率为~ 1ghz，超过了大多数磁性材料的铁磁共振（FMR）频率。因此，研究能够实现1ghz频率磁记录的新材料、磁化动力学和记录物理变得越来越迫切。在本项目中，我们提出以下建议：1)研究一种新的软磁材料，即Fe-Co-N薄膜（FeCoN），其饱和磁化强度为~24 kG，这将使硬盘驱动器的面记录密度更高（每平方英寸100 Gb）。2)研究1 GHz的磁化动力学和磁记录，这是一个重要的里程碑，如果付诸实践。3)评估新型FeCoN材料用于集成电感器的可行性，这是便携式无线通信设备等新兴应用所需要的。4)通过博士论文研究、本科生科研体验和课堂教学对研究生和本科生进行信息存储技术教育。

Soft magnetic films with low coercivity and high permeability are critical building blocks in numerous electromagnetic devices such as magnetic recording heads, integrated inductors (microinductors), integrated transformers, magnetic sensors, and micromachined motors. However, a lack of soft magnetic materials with a high saturation magnetization (20 kG), a large permeability (1000), and a large ferromagnetic resonance frequency (1 GHz), tends to be the bottleneck in these applications. For example, the data rate of hard disk drives is expected to be ~1 Gb/s (1 Gb = 1 billion bits) by year 2003. A data rate of 2 Gb/s corresponds to a recording frequencies of ~1 GHz, which exceeds the ferromagnetic resonance (FMR) frequency of most magnetic materials. Therefore, it is increasingly urgent to investigate new materials, magnetization dynamics, and recording physics which will enable magnetic recording at a frequency of 1 GHz. In this project, we propose the following: 1) Investigate a new soft magnetic material, namely Fe-Co-N films (FeCoN) with a saturation magnetization of ~24 kG, which will enable higher areal recording densities in hard disk drives (100 Gb per square inch). 2) Study magnetization dynamics and magnetic recording at 1 GHz, an important milestone if reduced to practice. 3) Evaluate the viability of the new FeCoN material for integrated inductors, which are desired for emerging applications such as portable wireless communication devices. 4) Educate graduate students and undergraduates about information storage technology via doctoral thesis research, research experience for under graduate (REU), and classroom teaching.