SOFT MAGNETIC PROPERTIES FOR SPUTTERED Fe FILMS IN Ar+N₂ PLASMA

Abstract

Magnetic properties of Fe films fabricated by facing target type d.c. magnetron sputtering method in Ar and Ar+N2 mixed plasma were investigated. Annealed films at 300°C shows excellent soft magnetic properties μeff=1600∼2000, saturation flux density BS=2.2T, film thickness 0.3μm. Structure analysis revealed that (110) sheet texture of α-Fe (b.c.c.) and expanded its lattice spacing by 0.4% from the bulk α-Fe are realized for the films with excellent soft magnetic properties. The optimum grain size of about 150A were also found. Calculation of total anisotropy energy in plane was made systematically as a function of lattice strain for the shear and tetragonality mode. After the calculation for the magnetostrictive anisotropy due to lattice strain of α-Fe about 0.4%, soft magnetic properties in the present film was found to be strongly concerned to the reduction of magnetocrystalline anisotropy K1 of α-Fe up to about 1/5.