Structural and magnetoresistive properties of magnetic tunnel junctions with half-metallic Co2 MnAl

Abstract

A series of polycrystalline full-Heusler Co2 MnAl thin films were deposited on Si (100) coated with thermo Si O2 by using different types of seed layers such as Cr, Mg, MgOCr, and MgO. The properties of the Co2 MnAl thin films such as the coercivity, atomic composition, and crystalline structure strongly depend on the deposition conditions and seed layers. Very soft Co2 MnAl thin films with coercivity of 8.3 Oe and small magnetostriction coefficient λS =1.43× 10-5 had been obtained when MgO was used as seed layer. Magnetic tunnel junctions with magnetoresistance ratio of 12%-19% by utilizing the Co2 MnAl as bottom ferromagnetic electrode have been successfully fabricated. © 2008 American Institute of Physics.