Tailoring the magnetic properties of Ni₈₁Fe₁₉ thin films by varying their thickness

Ni₈₁Fe₁₉O_y thin films with different thicknesses were obtained by atomic layer deposition. After a thermal reduction process, Ni₈₁Fe₁₉O_y films were converted to their strong Ni₈₁Fe₁₉ ferromagnetic phase, usually known as Permalloy. The different thicknesses were obtained by considering 500, 1000, 1500 and 2000 supercycles, which are defined as a cycle of NiCp₂/O₃ followed by another cycle of FeCp₂/O₃. The samples were characterized before and after the thermal reduction process with respect to their crystallinity, morphology and magnetism. In particular, the thermally reduced samples exhibit holes whose sizes increase significantly as the thickness of the samples also increases, affecting their magnetic behaviour. As Permalloy is widely used in many applications, its synthesis through atomic layer deposition is expected to introduce comparative advantages over other synthesis processes, opening up new possibilities for nanoelectronic devices.