Relationship between the structure and soft magnetic properties of FeRuGaSi films

The effect of annealing on the structure and magnetic properties (coercivity, saturation magnetostriction, and initial permeability) of (FeRu)x(GaSi) films (x=2.5, 3.4, and 3.9) sputtered on MnNi‐oxide and Li‐silicate glass‐ceramic substrates has been investigated. It is found that the best combination of soft magnetic properties (e.g., coercivity ≊0.3 Oe, permeability ≊1800 at 10 MHz, and magnetostriction ≪ 1 × 10^-6) is generally obtained after annealing between 450 and 500 °C independent of film composition, and subsequently deteriorate at higher annealing temperatures. This magnetic behavior is correlated with the crystal structure, grain size, and texture of the films as revealed by transmission electron microscopy and x‐ray diffraction. It is found that after annealing, all films exhibit best soft magnetic properties when they consist of mostly the B2 phase and their magnetic softness decreases with the formation of the DO3 phase.