Surface morphology and uniaxial magnetic anisotropy of Fe films deposited by dual ion beam sputtering

The relationship between the surface morphology and the magnetic characteristics of the Fe films deposited by dual ion beam sputtering was investigated. The voltage and current for the sputtering were fixed at 1200 V, and 50 mA, respectively. The Ar bombardment voltage V_A was varied in the range between 80 and 2000 V. The films mere deposited under the condition that the sputtered Fe atoms arrived at the incident angle of 45° and Ar ions bombarded the film surface normal to the plane. The films were composed of the grains elongated in a direction perpendicular to the incident direction of the sputtered Fe atoms at V_A below 400 V. The elongated direction changed parallel to the incident direction of the sputtered atoms at V_A above 800 V. The easy axis in the films plane also changed at V _A of 400~800 V. At V_A of 200 V, both the surface roughness and the grain size of the films showed the minimum values. The saturation magnetization 4 πM_S of the film took the maximum value of 21.5 kG and the coercivity H_C and anisotropy field H_K took the minimum value of 2.5 and 12 Oe, respectively. This result suggests that it was necessary to deposited the Fe films with smooth surface in order to improve the soft magnetic properties