  Interlayer exchange couplings were examined for Co2FeAl0.5Si0.5(CFAS)/Cr/CFAS
trilayered films grown on MgO (001) single crystal and thermally oxidized Si
substrates. The films were (001) epitaxial on MgO and (110) textured
polycrystalline on SiO2. Strong exchange couplings were observed for the films
with the 1.5 nm thick Cr spacer layer. A 90 degree coupling is dominant in the
(001) epitaxial film. In contrast, an antiparallel coupling exists in the
polycrystalline one. The relationship of interlayer couplings with the
structure is discussed.
