Structural, magnetic, and transport properties of full-Heusler alloy Co{sub 2}(Cr{sub 1-x}Fe{sub x})Al thin films

Journal Article · Wed Dec 01 04:00:00 EST 2004 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1810207· OSTI ID:20658104

Okamura, S; Goto, R; Sugimoto, S; Tezuka, N; Inomata, K ^[1]

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1. Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan)

The structural, magnetic, and transport properties are investigated for full-Heusler alloy Co{sub 2}(Cr{sub 1-x}Fe{sub x})Al (CCFA) thin films sputtered on thermally oxidized Si substrates at room temperature (RT). X-ray diffraction reveals that the films possess the B2 structure for x=0, decrease the atomic site ordering by substituting Fe for Cr (0.4IExIE0.6), and form the A2 structure for x=1. Both the magnetic moment and the Curie temperature of the films increase with increasing Fe content (x), although the moment for x<1 is significantly smaller than that of the calculated value for the L2{sub 1} structure. Magnetic tunnel junctions (MTJs) with CCFA films as either upper or bottom ferromagnetic layers are also fabricated by using metal masks. The maximum tunneling magnetoresistance (TMR) at RT for the MTJ was observed to be 19.1% for x=0.4 with the CCFA film as an upper ferromagnetic layer, despite the atomic disorder of the CCFA film. This is consistent with our previous TMR observation with the CCFA film as a bottom ferromagnetic layer, indicating that the CCFA film even with the B2 structure is a good candidate for future spintronic devices due to its disorder tolerance, high reproducibility, and large spin polarization.

• OSTI ID: 20658104
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 96; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM ALLOYS
COBALT ALLOYS
CURIE POINT
DEPOSITION
FERROMAGNETIC MATERIALS
HEUSLER ALLOYS
IRON ALLOYS
MAGNETIC MOMENTS
MAGNETORESISTANCE
OXIDATION
SILICON
SPIN ORIENTATION
SUBSTRATES
SUPERCONDUCTING JUNCTIONS
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
TUNNEL EFFECT
X-RAY DIFFRACTION