Ferromagnetic coupling field reduction in CoFeB tunnel junctions deposited by ion beam

Cardoso, S., Ferreira, R., Freitas, P.P., MacKenzie, M., Chapman, J.N., Ventura, J.O., Sousa, J.B. and Kreissig, U. (2004) Ferromagnetic coupling field reduction in CoFeB tunnel junctions deposited by ion beam. IEEE Transactions on Magnetics, 40(4), pp. 2272-2274. (doi: 10.1109/TMAG.2004.832147)

Abstract

In this paper, junctions with reduced H-f coupling were fabricated by ion beam deposition and oxidation, using CoFeB electrodes. The CoFeB layer has a strong (111) texture that can be the origin of lower H-f and coercivity when compared with CoFe. Junctions processed down to 2 x 4 mum(2) with 40- Angstrom-thick CoFeB bottom electrodes have 42% of tunneling magnetoresistance (TMR), (R x A similar to 400 Omega.mum(2)), H-c of similar to10 Oe and Hf of similar to2 Oe. CoFe-based junctions (R x A - 500 Omega.mum(2)) have lower TMR (similar to35%) and larger H-f (similar to5-6 Oe) and H-c (similar to12- 14 Oe). Local chemical composition analysis of the cross section indicated Fe-O segregation with very little Co grown on top of the barrier for CoFe-based junctions and not for CoFeB ones.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: MacKenzie, Dr Maureen and Chapman, Professor John
• Authors: Cardoso, S., Ferreira, R., Freitas, P.P., MacKenzie, M., Chapman, J.N., Ventura, J.O., Sousa, J.B., and Kreissig, U.
• Subjects: Q Science > QC Physics
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: IEEE Transactions on Magnetics
• ISSN: 0018-9464