We have studied structural and magnetic properties of quartz/Sm(25 nm)/Fe(1
5 nm) thin films by grazing incidence x-ray diffraction, atomic force micro
scopy, longitudinal magneto-optic Kerr effect, and superconducting quantum
interference device magnetometry. Both Sm land Fe layers exhibit growth in
a preferential direction with textured granular structure. The Fe layer is
composed of small elongated grains (36 nm long and 21 nm wide). The Fe grai
ns are monodomains and are all parallel aligned due to the texture effect.
Therefore, their magnetic shape anisotropy is summed, producing a final uni
axial in-plane magnetic anisotropy in the film. The Sm/Fe system is an anti
ferromagnetic/ferromagnetic bilayer exhibiting exchange bias coupling below
40 K. The long-range character of Sm-Fe spin interaction located near the
interface maintains this coupling, in spite of disorder effects at the inte
rface, such as Sm-Fe alloying, and results in a power-law decay with temper
ature for the exchange bias field(H-E). [S0163-1829 (99)09025-6].