Extremely large spin-polarization in Co2MnSi based magnetic tunnel junctions

DOI: 10.3379/jmsjmag.31.338

Authors: Y. Sakuraba (Tohoku University) , M. Hattori (Tohoku University) , M. Oogane (Tohoku University) , H. Kubota (National Institute of Advanced Science and Technology (AIST) (Japan)) , Y. Ando (Tohoku University) , A. Sakuma (Tohoku University) , N. D. Telling (CCLRC Daresbury Laboratory) , P. Keatley (University of Exeter) , G. Van Der Laan (CCLRC Daresbury Laboratory; Diamond Light Source) , E. Arenholz (Advanced Light Source, Lawrence Berkeley National Laboratory) , R. J. Hicken (University of Exeter) , T. Miyazaki (Tohoku University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The Magnetics Society Of Japan , VOL 31 , PAGES 338-343.

State: Published (Approved)
Published: January 2007

Abstract: We fabricated Co2MnSi/(Mg)/Al-O/CoFe MTJs using UHV magnetron sputtering. The interfacial chemical bond between Co2MnSi and Al-O was intensively optimized by changing plasma oxidation time for Al-O and by inserting a Mg layer. The Mg inserted layer between Co2MnSi and Al-O effectively suppressed the generation of interfacial magnetic impurities. Finally, we successfully observed a giant TMR ratio of 203% at 2 K in the MTJ with a 1.0 nm-Mg layer inserted. The spin-polarization for Co2MnSi estimated from this TMR ratio was 0.97-1.00, which indicated that an almost perfect spin-polarized state was achieved. We also investigated the relationship between the TMR ratio and the site-ordering level of Co2MnSi. As a result, we found that an L21-ordering state is not necessary to achieve high spin-polarization for Co2MnSi in MTJs.

Journal Keywords: magnetic tunnel junctions; tunnel magnetoresistance; half-metal; full-Heusler alloys; spin-polarization

Subject Areas: Physics, Materials

Facility: 6.3.1 at ALS

Added On: 04/08/2010 08:19

Discipline Tags:

Physics Magnetism Materials Science

Technical Tags: