Correlation between the magnetic imaging of cobalt nanoconstrictions and their magnetoresistance response

Fernández-Pacheco, A. , Serrano-Ramón, L.E., Tyliszczak, T., Chou, K.W., Córdoba, R., Szkudlarek, A., O'Brien, L., Kapusta, C., Ibarra, M.R. and De Teresa, J.M. (2012) Correlation between the magnetic imaging of cobalt nanoconstrictions and their magnetoresistance response. Nanotechnology, 23(10), 105703. (doi: 10.1088/0957-4484/23/10/105703)

Abstract

Scanning transmission x-ray microscopy (STXM) and magnetoresistance (MR) measurements are used to investigate the magnetic behavior of a nanoconstriction joining two micrometric electrodes (a pad and a wire). The reversal of the magnetization under variable external static magnetic fields is imaged. By means of a detailed analysis of the STXM images at the nanocontact area, the MR is calculated, based on diffusive anisotropic-MR. This MR agrees well with that obtained from electrical transport measurements, allowing a direct correlation between the MR signal and the magnetic reversal of the system. The magnetization behavior depends on the sample thickness and constriction dimensions. In 40 nm-thick samples, with 20 × 175 nm2 contact areas, the magnetization at the two sides of the constriction forms a net angle of 90°, with a progressive evolution of the magnetization structure between the electrodes during switching. The MR in those cases has a more peaked shape than with 20 nm-thick electrodes and 10 × 80 nm2 contact areas, where the magnetization forms 180°between them, with a wide domain wall pinned at the constriction. As a consequence of this configuration, a plateau in the MR is observed for about 20 Oe.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fernandez-Pacheco, Dr Amalio
• Authors: Fernández-Pacheco, A., Serrano-Ramón, L.E., Tyliszczak, T., Chou, K.W., Córdoba, R., Szkudlarek, A., O'Brien, L., Kapusta, C., Ibarra, M.R., and De Teresa, J.M.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Nanotechnology
• Publisher: IOP Publishing
• ISSN: 0957-4484
• ISSN (Online): 1361-6528