Synthetic antiferromagnet with Heusler alloy Co2 FeAl ferromagnetic layers

Abstract

Heusler alloy Co2FeAl was employed as ferromagnetic layers in Co2FeAl (3 nm)/Ru(x nm)/Co2FeAl (5 nm) synthetic antiferromagnet structures. The experimental results show that the structure with a Ru thickness of 0.45 nm is strongly antiferromagnetic coupled, which is maintained after annealing at 150 °C for 1 h. The structure has a very low saturation magnetization Ms of 425 emu/ cm3, a low switching field Hsw of 4.3 Oe, and a high saturation field H s of 5257 Oe at room temperature, which are favorable for application in ultrahigh density magnetic read heads or other magnetic memory devices. Crystal structure study testifies that the as-deposited Co2FeAl film is in the B2 phase. Therefore, Heusler alloys can be used to fabricate synthetic antiferromagnetic and it is possible to make "all-Heusler" spin valves or magnetic tunneling junctions with better magnetic switching properties and high magnetoresistance. © 2009 American Institute of Physics.