Improvement of the magnetic characteristics of multilayered Ni-Fe thin films by applying external in-plane field during sputtering

Ni₇₉Fe₂₁ single layers and multilayers composed of Ni₇₉Fe₂₁ layers and paramagnetic Al interlayers were deposited using the facing targets sputtering (FTS) apparatus. During layer deposition, the external field H_ex of 200 Oe along the film plane was applied parallel or transverse to the direction of the plasma confining field H_p of about 30 Oe in the FTS apparatus. The application of H_ex parallel to the H _p direction was not significantly effective for improving soft magnetic characteristics of the films. When H_ex was applied transverse to the H_p direction, the relative permeability μ_r of the Ni-Fe single layers 100 nm-thick was increased, while the coercivity H_c and the squareness ratio M_r/M_s of them were not varied. On the other hand, μ_r of the [Ni-Fe/Al]₅ multilayers was extremely and isotropically increased while M_r/M_s for the multilayers was decreased down to a half value