Chemical states of Co and Fe in a specularly reflective oxide layer in spin valves

Jongill Hong; Youngjun Lee, K. R.; Min Kyu Lee, K. R.; Ha Jin Song, K. R.; Hyun-Joon Shin; Yonggoo Yoo, K. R.; Jeongdae Suh, K. R.
December 2003
Applied Physics Letters;12/8/2003, Vol. 83 Issue 23, p4803
Academic Journal
In an examination of near-edge x-ray absorption fine structure spectra and magnetoresistance responses of a spin valve with a partially oxidized Co[sub 90]Fe[sub 10] layer, we found that oxygen preferentially reacted with the solute Fe rather than with the solvent Co, and the very oxidized Fe likely enhanced specular reflections leading to an increase in the magnetoresistance value. Most Fe oxides transformed into α-Fe[sub 2]O[sub 3], which further improved the magnetoresistance response after the spin valves were annealed. Our results show that obtaining appropriate oxide phases and controlling their quantity are the key to optimizing the magnetoresistance performance and magnetic properties of spin valves with specularly reflective oxide layers. © 2003 American Institute of Physics.


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