A comparative study of the microstructural and magnetic properties of <110> textured thin polycrystalline Fe100-xGax (10 ≤ x ≤ 35) films

In this work, we present a detailed analysis of the microstructure and magnetic properties of 50 ± 2 nm thick polycrystalline Fe100-xGax (10 ≤ x ≤ 35) films. Two sets of Fe100-xGax films were fabricated on Si <100> substrates with and without a forming field Hf present. Microstructural properties were studied using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and conversion electron Moessbauer spectroscopy (CEMS). Magnetic properties were studied using the magneto optical Kerr effect (MOKE) magnetometer. For all films, the <110> texture normal to the film plane was observed from XRD. No peaks corresponding to the ordered D03 or L12 phases were observed from XRD. Using CEMS, the disordered A2 phase was confirmed in all films. It was found that the magnetostriction in Set-1 (forming field Hf = 0) films was ∼40-50% higher compared to the Set-2 (Hf ≠ 0) films over the whole Ga composition range studied. Both film sets have a strong dependence of saturation field Hs on Ga composition. Set-1 films were magnetically isotropic but a weak uniaxial anisotropy was observed in Set-2 films. The saturation field Hs in Set-2 films was significantly lower compared to the Set-1 films. It was concluded that the Hf reduced Hs but also reduced effective saturation magnetostriction constant λeff in the films.