Temperature dependence of transport properties and exchange field of NiMn based spin valves

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

Authors

teixeira, j. m. (Author) Other; ventura, j. (Author) Other; negulescu, b. (Author) Other; araujo, j. p. (Author) FCUP; fermento, r. (Author) Other; sousa, j. b. (Author) FCUP; freitas, p. p. (Author) Other

Journal

Title: Journal of Magnetism and Magnetic Materials

Vol. 316

Pages: E973-E976

ISSN: 0304-8853

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 2 Citations

Other information

Authenticus ID: P-004-7XN

DOI: 10.1016/j.jmmm.2007.03.159

Abstract (EN): We studied ion beam deposited NiFe/CoFe/Cu/CoFe/NiMn spin valves (SVs) subjected to different thermal annealing to establish the exchange field (H-E) of the CoFe pinned layer. The magnetoresistive (MR) properties of the SVs were characterized by magnetotransport measurements. We found MR values of 7.5%, 12% and 14% at T = 20 K for SVs annealed at 453, 533 and 553 K, and observed a linear decrease of MR with increasing temperature for all SVs due to the excitation of spin waves. Our results also show that the exchange field H-E is approximately constant over the measured temperature range (20-300 K) for SVs annealed at 453 and 553 K (H-E approximate to 250) and 400 Oe, respectively), while the sample annealed at 533 K shows the usual decrease of H-E with temperature. These behaviors will be discussed in terms of structural differences between the measured SVs. An anomalous increase of the magnetoresistance at free layer switching in the ascending H-branch will be related with the enhancement of the pinned layer coercive field with decreasing temperature.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4