Interlayer coupling and magnetoresistance of MnIr-based spin valves: Dependencies on deposition rate, spacer thickness, and temperature

• Type: Article in International Scientific Journal
• Date: 2007

Authors

teixeira, jose miguel (Author) Other; ventura, joao oliveira (Author) Other; fermento, rui pedro (Author) Other; araujo, joao pedro (Author) FCUP; sousa, jodo bessa (Author) FCUP; freitas, susana cardoso (Author) Other; freitas, paulo jorge (Author) Other

Journal

Title: IEEE Transactions on Magnetics

Vol. 43

Pages: 3143-3145

ISSN: 0018-9464

Publisher: IEEE

Indexing

ISI Web of Knowledge - 14 Citations

Scopus - 13 Citations

Other information

Authenticus ID: P-004-932

DOI: 10.1109/tmag.2007.897352

Abstract (EN): We present a study of the dependence of Cu spacer interlayer coupling field (H-coupl) on the thickness t of the Cu and the deposition rate of the layers in spin valves (SVs). We considered two series of SVs made of NiFe/CoFe/Cu/CoFe/MnIr with Cu t ranging from 16 to 26 angstrom. In series 1, the deposition rates were 0.49 angstrom /s for Cu and 0.29 angstrom /s for CoFe. In series 2, the deposition rates were lower: 0.28 angstrom/s for Cu and 0.23 angstrom/s for CoFe. We found that lowering the deposition rates led to considerably lower H-coupl; about similar to 24 Oe in series 1 versus about 13 Oe in series 2, both with t = 19 angstrom and temperature T = 300 K. In both series, we observed an increase of H-coupl when t is reduced (as would be expected from Neel coupling dominance). The increase is weaker in the low deposition rate series. The difference is related to the different roughness of the ferromagnetic/nonferrornagnetic interfaces under the two deposition rates. We also measured the temperature dependence of the magnetoresistance (MR), starting at 20 K, observing values between 9% and 16% for series 2 and between 13% and 16% for series 1. MR then decreased linearly with increasing T for all SVs, vanishing at a temperature To of about 600 K, well below the bulk Curie point. However, we observed a striking difference between series I and series 2 in the temperature dependence of the dGMR/dT slopes, where GMR is the giant magnetoresistance.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 3