Interfacial coupling effect of Cr(2)O(3) on the magnetic properties of Fe(72)Ga(28) thin films

Here it is investigated the effect of the antiferromagnet Cr(2)O(3) on the magnetic properties of ferromagnetic Fe(72)Ga(28) thin films. Sputtered Fe(72)Ga(28) layers have their magnetization in the sample plane with a magnetic fluctuation that gives rise to magnetic ripple. In order to turn its magnetization into the out of plane (OOP) direction, it has been magnetically coupled with Cr(2)O(3) that has magnetic moments along the c-axis, that is the perpendicular direction when properly aligned. Cr(2)O(3) has been obtained from Cr oxidation, whereas Fe(72)Ga(28) has been deposited on top of it by sputtering in the ballistic regime. Although a uniaxial in-plane magnetic anisotropy is expected for Fe(72)Ga(28) thickness above 100 nm, the interfacial coupling with Cr(2)O(3) prevents this anisotropy. The formation of stripe domains in Fe(72)Ga(28) above a critical thickness reveals the enhancement of the out of plane component of the Fe(72)Ga(28) magnetization with respect to uncoupled layers. Due to the interface coupling, the Fe(72)Ga(28) magnetization turns into the out-of-plane direction as its thickness is gradually reduced, and a perpendicular magnetic anisotropy of 3·10(6) erg·cm(−3) is inferred from experimental results. Eventually, the coupling between Cr(2)O(3) and Fe(72)Ga(28) promotes an exchange-bias effect that has been well fitted by means of the random field model.