Electronic structures and magneto-transport properties of co-based Heusler alloy based magneto-resistance junctions

Abstract

A direct link between band structure and the ballistic transport property of full-Heusler alloys based Co2 YZ/Al/Co2 YZ 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 E F, the distance d of the two intersection points of Co2 YZ and Al at E F, and the absolute maximum of the energy lying in the E F-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 E F. In general, an intuitively illustrated diagram is proposed to clarify the relationship between the probability of electron transition and the current magnitude.