Behavior of Magnetic Domains in Single Magnetic Nanowire with Shallow Trench along Length Direction Observed by Magnetic
- PDF / 4,841,243 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 67 Downloads / 197 Views
Behavior of Magnetic Domains in Single Magnetic Nanowire with Shallow Trench along Length Direction Observed by Magnetic Force Microscopy Mitsunobu Okuda1, Yasuyoshi Miyamoto1, Eiichi Miyashita1 and Naoto Hayashi1 1 NHK Science & Technology Research Laboratories, 1-10-11 Kinuta, Setagaya-ku, Tokyo, 157-8510, Japan ABSTRACT We have proposed new magnetic memories using parallel-aligned nanowires without mechanical moving parts, in order to achieve the ultra high transfer rate of more than 144 Gbps for Super Hi-Vision TV. In the magnetic memory using nanowires, the data are stored as the magnetic domains with up or down magnetization in magnetic nanowires, and the domains are shifted quite faster by applying optimum current along the nanowire direction for data writing and reading purpose. Since the electric circuits and the insulation space between the neighbor nanowires are necessary for moving the magnetic domain walls, the areal recording density is essentially reduced as compared with that of conventional hard disk drives. In this study, in order to increase the areal recording density of magnetic nanowire memory, we have tried to act one magnetic nanowire as the virtual multiple data tracks. The shallow scratched trench was introduced using scanning probe microscopy along the length direction on the surface of a single nanowire to form multiple internal tracks, and we have succeeded in realizing a couple of virtual tracks states. INTRODUCTION We have proposed the “Super Hi-Vision (SHV)” ultra-high definition TV system with 8Kx4Kpixels as the next-generation TV system, where ultra high speed recording device with the transfer rate of more than 144 Gbps is required for the uncompressed SHV data storage [1]. Unfortunately, only the storage capacity has been focused in the recording device research field and it has increased extremely, while the recording speed, i.e. data transfer rate, has not increased as fast as the trend of capacity, because the current hard disk drives have enough recording speed for the personal computer use or for storing the motion pictures like high definition TV with 2Kx1K pixels. From the view point of the high-speed recording application, the behavior of the magnetic domain walls in magnetic nanowires may solve this issue, where the faster domain wall motions by applying currents along the nanowires [2]-[3] have been utilized for the race-track memories [4]. The speed of domain wall motion is about 10-20 times higher than the relative speed between the head and the media in conventional hard disk drives from the recent works [5]. Therefore, in order to speed-up the storage devices, we have focused on the magnetic memories using many parallel-aligned nanowires without mechanical moving parts. Recently, scanning probe microscopy (SPM) and its related micro-fabrication technology is widely used for the research of the current-driven domain wall motion in magnetic nanowires. Here, one magnetic nanowire is usually used as a single ‘recording track’. Because electric circuits for moving the mag
Data Loading...
