AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Thursday Sessions
       Session MI+NS-ThM

Invited Paper MI+NS-ThM1
1-D Propagation of a Magnetic Domain Wall in Submicron Magnetic Wire

Thursday, October 28, 1999, 8:20 am, Room 618/619

Session: Patterned or Self-Assembled Magnetic Nanostructures
Presenter: T. Ono, Keio University, Japan
Authors: T. Ono, Keio University, Japan
H. Miyajima, Keio University, Japan
K. Shigeto, Kyoto University, Japan
K. Mibu, Kyoto University, Japan
N. Hosoito, Kyoto University, Japan
T. Shinjo, Kyoto University, Japan
Correspondent: Click to Email
A novel method to detect single domain wall motion in a submicron magnetic wire by utilizing the giant magnetoresistance (GMR) effect is presented.@footnote 1@ Recent developments of nanolithography techniques make it possible to prepare submicron dots or wires with well-defined shape, leading to the current attention on the quantum phenomena in mesoscopic magnetic materials, such as macroscopic quantum tunneling and macroscopic quantum coherence. However, the direct magnetization measurements of mesoscopic magnetic materials are practically difficult because of their small volume, and have been performed using samples consisting of a huge number of presumably identical particles. As a result, the essential magnetic properties of a single particle or wire were masked by the inevitable distribution of size or shape. Up to now, quantitative measurements on dynamical properties of a domain wall in a submicron magnetic wire, such as velocity estimation were almost impossible. The method described in this paper has a great advantage to detect a single magnetic domain wall motion, since the GMR change is directly proportional to the magnitude of the switching layer magnetization in a magnetic wire. It should be noticed that the domain wall position can be determined by this method as a function of time, and, thus, we can measure the velocity of a single domain. The wall velocity linearly depends on the applied magnetic field H and is described as v = µ(H -H@sub 0@), where v is the wall velocity, µ so-called wall mobility. In case of NiFe wire 40 nm in thickness and 500 nm in width, it was obtained that µ = 2.6 (m/sOe), and H@sub 0@ = 38 (Oe) at 100 K. @FootnoteText@ @footnote 1@ T. Ono, H. Miyajima, K. Shigeto, K. Mibu, N. Hosoito and T. Shinjo, Science, 284 (1999) 468-470.