Perpendicular Magnetic Anisotropy in Co2 FeAl Thin Films: Effect of Annealing Temperature

• Published in: IEEE transactions on magnetics Vol. 51; no. 11; pp. 1 - 4
• Main Authors: Belmeguenai, M., Gabor, M. S., Roussigne, Y., Zighem, F., Cherif, S. M., Tiusan, C.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anisotropic magnetoresistance; Annealing; Ferromagnetic resonance; Heusler thin films; Magnetic resonance; Magnetism; Magnetization; magnetization dynamics; Perpendicular magnetic anisotropy; Heusler thin films; perpendicular magnetic anisotropy (PMA); Ferromagnetic (FM) resonance; magnetization dynamics
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2015.2435815

Co 2 FeAl (CFA) thin films of various thicknesses (1 nm ≤ d ≤ 10 nm) have been grown on (001) MgO single-crystal substrates and annealed at different temperatures (T a ). Their magnetic properties have been studied by vibrating sample magnetometry, broadband microstrip ferromagnetic resonance (MS-FMR), and Brillouin light scattering (BLS). The effective magnetization, deduced from the fit of MS-FMR and BLS measurements, linearly decreases with the inverse thickness (1/d) for all the annealing temperatures. This allows quantifying perpendicular surface anisotropy constants of 1.46, 1.71, and 1.29 erg/cm 2 for T a = 215 °C, 265 °C, and 315 °C, respectively. The perpendicular magnetization is achieved for the CFA films below a critical thickness that increases with increasing T a . Moreover, the fourfold anisotropy fields, measured in the in-plane magnetized films, increase with T a and decrease with respect to the CFA inverse thickness.