Electronic Structures and Magneto-Transport Properties of Co-Based Heusler Alloy Based Magneto-Resistance Junctions

A direct link between band structure and the ballistic transport property of full-Heusler alloys based Co2YZ/Al/Co2YZ trilayers（Y = Sc, Ti, V, Cr, Mn and Fe; Z = Al, Si and Ge） has been studied by firstprinciples calculations. It is found that the transport efficiency is determined primarily by three factors related to band structure: the shape of the band crossing Fermi energy EF, the distance d of the two intersection points of Co2YZ and Al at EF, and the absolute maximum of the energy lying in the EF-crossing band, |Emax|. The transmission coefficient distribution patterns imply that the affected factor of magneto-resistance（MR） ratio is attributed to the band features around EF. In general, an intuitively illustrated diagram is proposed to clarify the relationship between the probability of electron transition and the current magnitude.