Effects of argon pressure on magnetic properties and low-field magnetostriction of amorphous TbFe films

Amorphous TbFe films were fabricated by DC magnetron sputtering, and the effects of argon pressures on the microstructure, magnetic properties and the low magnetic field magnetostrictions of the samples were explored. It is found that with the increase of argon pressure, the surface smoothness and the compactness of TbFe films are declined. At lower argon pressure, maze magnetic domains exist, and it possesses, hence, stronger perpendicular anisotropy. With the increase in argon pressure, the domain walls become gradually wider and the contrast of domain image appears to be less sharper. It implies that the magnetic anisotropy direction of the films gradually changes from perpendicular to parallel to the film plane with larger argon pressure. In addition, the magnetization is stronger with increase in argon pressure, and reaches its maximum value at 0.6 Pa. After that, the magnetization begins to decrease with further increase in argon pressure. However, the coercivity of the films decreases monotonically with the increase in the argon pressure. At low magnetic fields, the magnetostriction of amorphous TbFe films becomes larger with increase in the argon pressure. After reaching its maximum value at 0.6 Pa, a decrease was observed with further increase in argon pressure.