Microstructure, In-Plane Magnetic Properties, and Surface Energy of Co 60 Fe 20 V 20 Thin Films.

Co60Fe20V20 thin films with thicknesses ranging from 3 to 13 nm were sputtered onto a Si(100) substrate at room temperature (RT). Captured selected-area diffraction patterns (SADs) and high-resolution cross-sectional transmission electron microscopy (HR X-TEM) images revealed that the microstructures of the Co60Fe20V20 thin films were amorphous. The hysteresis loop of the thinner Co60Fe20V20 thin films displayed the in-plane magnetic anisotropy, possibly as a result of atmo-spheric exposure. A comparison of saturation magnetization (Ms) and thicknesses indicated a concave-down phenomenon due to magnetic coupling. In addition, the coercivity (Hc) also suggested a concave-down trend because the thinner Co60Fe20V20 thin films had a greater pining sites effect and rendered the domain wall difficult to move, resulting in higher Hc and lower Ms. The contact angles were smaller than 90°, indicating that the films were hydrophilic. The surface energy, which had a close positive correlation with adhesion ranged from 22.3 to 33.3 mJ/mm2 and displayed a concave-up trend. The critical thickness was 5 nm. Based on the magnetic and surface energy results, the optimal thickness of Co60Fe20V20 films is 7 nm due to high Ms, low Hc, and strong adhesion. They are suitable for use as a free layer of the magnetic tunneling junction and can be applied in magnetic recording media.