Interfacial coupling effect of Cr2O3 on the magnetic properties of Fe72Ga28 thin films

• Published in: Scientific reports 2021-06, Vol.11 (1), p.13429-13429, Article 13429
• Main Authors: Hontecillas, I., Maicas, M., Andrés, J. P., Ranchal, R.
• Format: Article
• Language: English
• Subjects: 639/301; 639/766; 639/925; Anisotropy; Humanities and Social Sciences; Magnetic properties; Magnetism; multidisciplinary; Oxidation; Science; Science (multidisciplinary); Thin films
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-92640-y

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.