Deposition of amorphous Co-Ta and Co-Zr thin films by means of double ion beam sputtering

Co-Zr and Co-Ta amorphous films with soft magnetic properties have been deposited by double ion beam sputtering. And the dependence of their crystal structure and magnetic properties on preparation conditions, especially on the ion bombardment during deposition, has been investigated. The composition range of Co content where the amorphous films are obtained becomes wider as the energy of bombarding ions increases; the amorphous films are obtained in the range of Co content as high as 98 at.% for Co-Zr system and 94.3 at.% for Co-Ta system. The amorphous Co98Zr2and Co94.3Ta5.7films show saturation magnetization 4πMs at room temperature about 16 kG and 15 kG, respectively. These amorphous films have low coecive force Hc below 0.5 Oe. Effective permeability μeffof the Co-Zr films increases with an increase of the temperature of annealing in rotating field and with an increase of the energy of bombarding ions;μeffof 2500 is obtained for the films deposited with 120 eV ion beam bombardment by setting annealing temperature about 300°C. μeffof the Co-Ta films decreases with an increase of the energy of bombarding ions;μeffof 2500 and 5200 is obtained for the films deposited with 120 eV ion beam bombardment and for those deposited without it.