Microstructures and magnetic properties of L10 FePt films deposited on NaCl-type films

• Published in: Thin solid films 2013-10, Vol.544, p.504-508
• Main Authors: Sun, T.H., Chen, S.C., Su, W.H., Chen, J.R.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; FePt thin films; Magnetic properties; MgO underlayer; NiO underlayer; Perpendicular magnetic anisotropy; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.01.038

A single-layered FePt film of 30nm thickness with perpendicular magnetic anisotropy is achieved by depositing the film onto a heated Si(100) substrate at 620°C. Its perpendicular coercivity (Hc⊥), saturation magnetization (Ms) and perpendicular squareness (S⊥) are as high as 1113kA/m, 0.594Wb/m2 and 0.96, respectively. The perpendicular magnetic anisotropy degrades when a 5-nm NiO film is introduced under this single-layered film. Upon further increasing the thickness of the NiO film to 10nm, the Hc⊥ of the single-layered film decreases greatly to around 330kA/m. Compared to a NiO underlayer, the Hc⊥ of the FePt film remains above 1000kA/m when a 10-nm MgO underlayer is introduced. Furthermore, when the thickness of the MgO underlayer is decreased to 5nm, the perpendicular magnetic anisotropy of the single-layered FePt film is further enhanced. Its Hc⊥ stays high at 1081kA/m; however, S⊥ increases significantly to 1. ► A thin MgO underlayer enhances the perpendicular magnetic anisotropy of FePt film. ► A NiO underlayer degrades the perpendicular magnetic anisotropy of the film. ► Ni atoms diffuse from NiO underlayer into FePt layer forming NiFe compounds.