Magnetic tunnel junctions (MTJs) with stacking structures of Co 2MnSi/Al-O/CoFe and Co2MnSi/Al-O/Co2MnSi were fabricated using a magnetron sputtering system. Co2MnSi/Al-O/CoFe-MTJ and Co2MnSi/Al-O/Co2MnSi-MTJ exhibited extremely large tunnelling magnetoresistance ratios of 159% and 570%, respectively, at low temperature, indicating the half-metallicity of Co2MnSi. We investigated the bias voltage dependence of tunnelling conductance (dI/dV-V) for each MTJ in order to clarify the band structure around the Fermi level in Co2MnSi. The observed dI/dV-V curves for both MTJs reveal a clear half-metallic energy gap at 350-400 meV for Co2MnSi, with an energy separation of just 10 meV between the Fermi energy and the bottom edge of the conduction band.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Acoustics and Ultrasonics
- Surfaces, Coatings and Films