Growth of Textured CoFe₂O₄Thin Films on Platinized Silicon Prepared by a Sol-Gel Method

Abstract

We fabricated textured polycrystalline CoFe 2 O 4 thin films on Pt(111)/TiO 2 /SiO 2 /Si substrate through a sol-gel method. We varied the thickness of the films, by using precursor solutions with different concentrations of 0.1, 0.2, and 0.3 M, and by depositing 5, 8, or 10 layers on the substrate by spin-coating. X-ray diffraction spectra indicated that when the precursor concentration of the solution was higher than 0.1 M, the spin-coated films were preferentially oriented in the direction. Inspection of the surface morphology by scanning electron microscopy revealed that CoFe 2 O 4 thin films prepared with 0.2 M solution and 5-time spin-coatings had smoother surface, as compared to the other conditions. Each coating had an average thickness of about 50 nm. The magnetic properties measured by vibrating sample magnetometer showed magnetic anisotropy, as evidenced from the difference in the in-plane and out-of-plane hysteresis loops, which we attributed to the textured orientation of the CoFe 2 O 4 thin films.

Regulation of the forming process and the set voltage distribution of unipolar resistance switching in spin-coated CoFe2O4 thin films

“…From our previous work [20], the thickness of the CFO films post-annealed at 700°C was about 50 to 60 nm for one-time spin-coating, and the CFO thin film thickness increased almost linearly with the number of coating layers. In this work, the thickness of the CFO films was varied by adjusting the number of spin-coated layers from 1 to 4, and the CFO films were labeled as CFO-1, CFO-2, CFO-3, and CFO-4 accordingly.…”

“…The procedures from coating to pre-annealing were repeated up to the desired thickness. More detailed preparation procedures have been reported previously [20]. The CFO thin films were then exposed to different heat treatment process, i.e., no further annealing (CFO-RT), post-annealed at 500°C (CFO-500) or 700°C (CFO-700) for 1 h in air ambient.…”

Regulation of the forming process and the set voltage distribution of unipolar resistance switching in spin-coated CoFe2O4 thin films

“…In addition to the heat treatment effect, we further studied the dependence of RS behavior on the thickness of the CFO thin film. From our previous work [20], the thickness of the CFO films post-annealed at 700°C was about 50 to 60 nm for one-time spin-coating, and the CFO thin film thickness increased almost linearly with the number of coating layers. In this work, the thickness of the CFO films was varied by adjusting the number of spin-coated layers from 1 to 4, and the CFO films were labeled as CFO-1, CFO-2, CFO-3, and CFO-4 accordingly.…”