Synthetic antiferromagnet with Heusler alloy Co2FeAl ferromagnetic layers

Abstract

Heusler alloy Co2FeAl was employed as ferromagnetic layers in Co2FeAl/Ru/Co2FeAl synthetic antiferromagnet structures. The experimental results show that the structure with a Ru thickness of 0.45 nm takes on strongly antiferromagnetic coupling, which maintains up to 150 oC annealing for 1 hour. The structure has a very low saturation magnetization Ms of 425 emu/cc, a low switching field Hsw of 4.3 Oe and a high saturation field Hs of 5257 Oe at room temperature, which are favorable for application in ultrahigh density magnetic read heads or other magnetic memory devices. XRD study testifies that the as-deposited Co2FeAl film is in B2 phase. Therefore Heusler alloys can be used to fabricate SyAF and it is possible to make "all-Heusler" spin-valves or magnetic tunneling junctions with better magnetic switching properties and high magnetoresistance.