Magnetic anisotropy and coercivity in magnetic thin films

Abstract

Magnetocrystalline anisotropy was investigated in Al doped barium ferrite (Al-BaM) nanoparticles and thin films. Doping of Al leads to a higher coercivity in BaAl2Fe10O19 nanoparticles. Shape anisotropy was studied in sputtered nickel thin films. A columnar structure, which might induce the shape anisotropy, was found by our TEM observations. Both SiO2 doped and pure cobalt ferrite thin films were synthesized using a sputtering method in order to study the stress-induced anisotropy. After adding a small amount of SiO2 to cobalt ferrite, the deposited films on the naturally oxidized silicon substrate exhibited a strong perpendicular anisotropy, while the pure cobalt ferrite films showed magnetic isotropy. All along our study we considered that anisotropies: -magnetocrystalline anisotropy, shape anisotropy, and stress-induced anisotropy play an important role in magnetic materials, especially in thin films, and any of them may be predominant in special circumstances.