Thickness dependence of magnetic properties in (Fe)0.73(Sm2O3)0.27 nano-granular films

Graphical abstract: Display Omitted Research highlights: → (Fe)0.73(Sm2O3)0.27 nano-granular films with thicknesses varying from 46 nm to 220 nm were fabricated by a RF magnetron sputtering method. → There is a critical thickness tc around 65 nm in the (Fe)0.73(Sm2O3)0.27 nano-granular films. Below tc, the films possess an in-plane uniaxial anisotropy and lower Hc. → The spectrum of the film can be ascribed to the uniform coherent spin procession. → Above tc, the films exhibit a small perpendicular anisotropy, higher Hc and stripe domains, and the stripe period increases with increasing film thickness. → The increasing film thickness leads to an monotonously increase of the permeability (imaginary part), and a shift of resonance frequency towards the low frequency and a decrease of resonance linewidth for the films with thickness larger than 120 nm. - Abstract: (Fe)0.73(Sm2O3)0.27 nano-granular films with thicknesses varying from 46 nm to 220 nm were fabricated by a RF magnetron sputtering method. The static and dynamic magnetic properties of these films on thickness dependence have been investigated in detail. High-resolution transmission electron micrograph shows that the films consist of Fe granules and crystalline Sm2O3 matrix. The results reveal that there is a critical thickness tc around 65 nm in the (Fe)0.73(Sm2O3)0.27 nano-granular films. Below tc, the films possess an in-plane uniaxial anisotropy and lower Hc. Above tc, the films exhibit a small perpendicular anisotropy, higher Hc and stripe domains, and the stripe period increases with increasing film thickness. The dynamic permeability spectra measured over the frequency range of 0.1-7 GHz display one resonance peak for all thicknesses. The spectrum of the film with thickness below tc can be ascribed to the uniform coherent spin procession. Above tc, the increasing film thickness leads to an monotonously increase of the permeability (imaginary part), and a shift of resonance frequency towards the low frequency and a decrease of resonance linewidth for the films with thickness larger than 120 nm.