  Indirect magnetoelectric effect has been studied in
magnetostrictive-film/substrate/piezoelectric-actuator heterostructures. Two
different substrates have been employed: a flexible substrate (Young's modulus
of 4 GPa) and a rigid one (Young's modulus of 180 GPa). A clear optimization of
the indirect magnetoelectric coupling, studied by micro-strip ferromagnetic
resonance, has been highlighted when using the polymer substrate. However, in
contrast to the rigid substrate, the flexible substrate also leads to an a
priori undesirable and huge uniaxial anisotropy which seems to be related to a
non equibiaxial residual stress inside the magnetostrictive film. The strong
amplitude of this non equibiaxiallity is due to the large Young's modulus
mismatch between the polymer and the magnetostrictive film which leads to a
slight curvature along a given direction during the elaboration process and
thus to a large magnetoelastic anisotropy.
