Interface roughness induced asymmetric magnetic property in sputter-deposited Co/CoO/Co exchange coupled trilayers

Journal Article · Sun Apr 01 04:00:00 EDT 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3679430· OSTI ID:22036860

Wang, J; Sannomiya, T; Shi, J; Nakamura, Y ^[1]

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1. Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8552 (Japan)

The effect of interface roughness on magnetic properties of exchange coupled polycrystalline Co/CoO(t{sub AF})/Co trilayers has been investigated by varying antiferromagnetic layer (CoO) thickness. It has been found that the upper CoO/Co interface becomes rougher with increasing CoO layer thickness, resulting in stronger exchange bias of the upper interface than the lower one. The interfacial exchange coupling is strengthened by the increase of defect-generated uncompensated antiferromagnetic spins; such spins form coupling with spins in the Co layer at the interface. As a result, the CoO layer thickness dependence of exchange bias is much enhanced for the upper Co layer. The transition from anisotropic magnetoresistance to isotropic magnetoresistance for the top Co layer has also been found. This could be attributed to the defects, probably partial thin oxide layers, between Co grains in the top Co layer that leads a switch from spin-orbit scattering related magnetoresistance to spin-dependent electron scattering dominated magnetoresistance.

• OSTI ID: 22036860
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 111; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
ANTIFERROMAGNETIC MATERIALS
ANTIFERROMAGNETISM
COBALT
COBALT OXIDES
DEPOSITION
EXCHANGE INTERACTIONS
INTERFACES
L-S COUPLING
LAYERS
MAGNETIC PROPERTIES
MAGNETORESISTANCE
POLYCRYSTALS
ROUGHNESS
SPIN
SPUTTERING