Mao Sining
Seagate Technology, Recording Head Operations, 7801 Computer Avenue South, Minneapolis, MN 55435, USA.
J Nanosci Nanotechnol. 2007 Jan;7(1):1-12.
Spintronics is emerging to be a new form of nanotechnologies, which utilizes not only the charge but also spin degree of freedom of electrons. Spin-dependent tunneling transport is one of the many kinds of physical phenomena involving spintronics, which has already found industrial applications. In this paper, we first provide a brief review on the basic physics and materials for magnetic tunnel junctions, followed more importantly by a detailed coverage on the application of magnetic tunneling devices in magnetic data storage. The use of tunneling magnetoresistive reading heads has helped to maintain a fast growth of areal density, which is one of the key advantages of hard disk drives as compared to solid-state memories. This review is focused on the first commercial tunneling magnetoresistive heads in the industry at an areal density of 80 approximately 100 Gbit/in2 for both laptop and desktop Seagate hard disk drive products using longitudinal media. The first generation tunneling magnetoresistive products utilized a bottom stack of tunnel junctions and an abutted hard bias design. The output signal amplitude of these heads was 3 times larger than that of comparable giant magnetoresistive devices, resulting in a 0.6 decade bit error rate gain over the latter. This has enabled high component and drive yields. Due to the improved thermal dissipation of vertical geometry, the tunneling magnetoresistive head runs cooler with a better lifetime performance, and has demonstrated similar electrical-static-discharge robustness as the giant magnetoresistive devices. It has also demonstrated equivalent or better process and wafer yields compared to the latter. The tunneling magnetoresistive heads are proven to be a mature and capable reader technology. Using the same head design in conjunction with perpendicular recording media, an areal density of 274 Gbit/in2 has been demonstrated, and advanced tunneling magnetoresistive heads can reach 311 Gbit/in2. Today, the tunneling magnetoresistive heads have become a mainstream technology for the hard disk industry and will still be a technology of choice for future hard disk products.
自旋电子学正在成为一种新型的纳米技术，它不仅利用电子的电荷自由度，还利用其自旋自由度。自旋相关隧穿输运是众多涉及自旋电子学的物理现象之一，已经在工业上得到应用。在本文中，我们首先简要回顾磁隧道结的基本物理和材料，更重要的是，随后详细介绍磁隧道器件在磁数据存储中的应用。隧穿磁阻读取头的使用有助于保持面密度的快速增长，这是硬盘驱动器相对于固态存储器的关键优势之一。本综述聚焦于行业中首款商业隧穿磁阻头，其应用于笔记本电脑和台式机希捷硬盘驱动器产品，采用纵向介质，面密度约为80至100 Gbit/in²。第一代隧穿磁阻产品采用底部堆叠的隧道结和对接硬偏置设计。这些磁头的输出信号幅度比同类巨磁阻器件大三倍，导致比特误码率比后者提高了0.6个数量级。这使得组件和驱动器的良品率很高。由于垂直结构的热耗散得到改善，隧穿磁阻头运行时温度更低，使用寿命更长，并且已证明其静电放电鲁棒性与巨磁阻器件相似。与后者相比，它还展示出相当或更好的工艺和晶圆良品率。隧穿磁阻头已被证明是一种成熟且性能优良的读取技术。使用相同的磁头设计结合垂直记录介质，已实现274 Gbit/in²的面密度，先进的隧穿磁阻头可达到311 Gbit/in²。如今，隧穿磁阻头已成为硬盘行业的主流技术，仍将是未来硬盘产品的首选技术。
