Effect of the annealing temperature on dynamic and structural properties of Co₂FeAl thin films

Abstract

Abstract. 10 nm and 50 nm thick Co 2 FeAl (CFA) thin films have been deposited on thermally oxidized Si(001) substrates by magnetron sputtering using a Tantalum cap layer and were then ex-situ annealed at 415°C, 515°C and 615°C during 15 minutes in vacuum. X-rays diffraction indicates that films CFA are polycrystalline and exhibit an in-plane isotropy growth. Ferromagnetic resonance measurements, using a microstrip line (MS-FMR), reveal a huge interfacial perpendicular magnetic anisotropy and small in-plane uniaxial anisotropy both annealing temperature-dependent. The MS-FMR data also allow concluding that the gyromagnetic factor remains constant and that the exchange stiffness constant increases with annealing temperature. Finally, the FMR linewidth decreases with increasing annealing temperature due to the enhancement of the chemical order, and allow deriving a very low intrinsic damping parameter (1.3x10 -3 at 615°C).

The Structural, Magnetic, and Transport Properties of the Pulsed Laser‐Deposited Co2FeAl Thin Films

“…The H c is usually below 50 Oe in either single or polycrystalline films prepared by magnetron sputtering, and it decreases with the increase of annealing temperature from RT to about 600 C, as shown in Figure 3c, which is attributed to the improvement of crystalline structure and chemical order. [25,26] For PLD-prepared CFA films in our work, the H c is enhanced with the increase of T s from 600 to 700 C. Similar behavior has been found when T s is increased from 300 to 600 C. As H c is an extrinsic magnetic parameter, the possible reasons leading to the increase of H c as T s are as follows:…”