Effect of Cr interlayers on texture and magnetic properties of FeSi films with micrometer thickness

Magnetised soft ferromagnetic films with micrometer thicknesses can be used as π-flippers in spin-echo small-angle neutron scattering instruments. An FeSi film with a total thickness of 2000 nm separated by Cr interlayers (each 10 nm thick) was fabricated using direct-current magnetron sputtering. The thickness of each FeSi layer was 100 nm between adjacent Cr interlayers. Hysteresis loop measurements were performed to characterise the magnetic properties of the FeSi films. X-ray diffraction measurements, high-resolution transmission electron microscopy, and selected-area electron diffraction were used to characterise the texture. Results demonstrated that the saturation magnetisation of the FeSi film separated by Cr interlayers was higher and its coercivity was lower than those of the FeSi film separated by Ta interlayers because of different texture of FeSi layer. The FeSi film separated by Cr interlayers featured FeSi (210) and FeSi (221), and the Cr interlayers presented Cr (110). The FeSi layer between the Cr interlayers demonstrated structural coherency with the upper FeSi layer, and continuity of the lattice fringes from the Cr grains to the FeSi layers was observed. Therefore, degradation in the soft magnetic properties of FeSi films can be prevented by the insertion of Cr interlayers.