Influence of nano-oxide layer on the giant magnetoresistance and exchange bias of NiMn/Co/Cu/Co spin valve sensors

Autor:	Senthilnathan Mohanan, M. K. Kinyanjui, Andrey Chuvilin, Ulrich Herr, Ute Kaiser, Anoop Gupta
Rok vydání:	2010
Předmět:	chemistry.chemical_compound Materials science Exchange bias Condensed matter physics Magnetic structure chemistry Transmission electron microscopy Annealing (metallurgy) Spin valve Oxide General Physics and Astronomy Antiferromagnetism Giant magnetoresistance
Zdroj:	Journal of Applied Physics. 107:093910
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.3407569
Popis:	NiMn is an interesting material for achieving a high exchange bias in spin valve systems. We investigated the influence of a nano-oxide layer (NOL) inserted in the pinned Co layer on the magnetotransport properties of NiMn/Co/Cu/Co spin valve sensors. The samples were annealed at 350 °C for 10 min to achieve the antiferromagnetic L10 ordered structure of NiMn. The NOL has been characterized by small angle x-ray reflectivity, transmission electron microscopy (TEM), and energy filtered TEM. The inclusion of the NOL leads to an increase in the giant magnetoresistance (GMR) by 20 % indicating a high degree of specular reflection at the NOL. For NOL positions close to the NiMn/Co interface, a decrease in the exchange bias field (Hex) is observed. The best combination of high GMR value and large Hex was found when the NOL was inserted in the center of the pinned Co layer.
Databáze:	OpenAIRE
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