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The Tb(Fe0.55Co0.45)1.5 films were fabricated by rf magnetron sputtering from a composite target. Samples were investigated by means of x-ray diffraction, vibrating sample magnetometer, conversion electron Mössbauer spectra, and magnetostriction measurements. The as-deposited film is an amorphous alloy with a perpendicular magnetic anisotropy and an intrinsic magnetostriction λ=1080×10−6 in an applied field of 0.7 T. In this state, it was determined that the hyperfine field Bhf=23.5 T and the cone-angle between the Fe moment direction and the film-normal direction β=12°. After annealing in the temperature range of TA=250–450 °C the amorphous structure still remained, however the anisotropy was changed to a parallel one. The soft magnetostrictive behavior has also been improved by these heat treatments: the parallel magnetostriction λ∥=465×10−6 was almost developed in low applied fields of less than 0.1 T and, especially, a huge magnetostrictive susceptibility χλ=dλ∥/d(μ0H)=1.8×10−2 T−1 was obtained at μ0H=15 mT.

The structure and magnetic properties of the rf-sputtered Fe/Ti multilayers with the fixed Ti-layer thicknesses (series 1: tTi=1 nm and series 2: tTi=2 nm) and the variable Fe-layer thicknesses (1 nm⩽tFe⩽6 nm) have been studied by the high-angle x-ray diffraction, transmission electron microscopy, conversion electron Mössbauer spectrometry and vibrating sample magnetometer. The results show that Fe layers with thicknesses less than 1 nm are alloyed forming an amorphous TiFe2 phase. As the Fe-layer thickness increases, the iron-rich crystalline Fe–Ti alloy is formed at the interface and, finally, the pure crystalline α-Fe and Ti layers appear in the center of the individual subsystems. The spin orientation in Fe layers is then strongly aligned in the film plane. However, in the interfacial region, perpendicular spin orientation is evidenced. This perpendicular magnetic anisotropy is associated to the Fe-rich alloy at the interface and is discussed in terms of reduced symmetry effects on the band structure of the 3d(Fe)-itinerant electrons.

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