  Magnetic and magnetostrictive hysteresis loops of TbCo/CoFe multilayers under
field applied along the hard magnetization axis are studied using vectorial
magnetization measurements, optical deflectometry and magneto optical Kerr
microscopy. Even a very small angle misalignment between hard axis and magnetic
field direction is shown to drastically change the shape of magnetization and
magnetostrictive torsion hysteresis loops. Two kinds of magnetic domains are
revealed during the magnetization: big regions with opposite rotation of
spontaneous magnetization vector and spontaneous magnetic domains which appear
in a narrow field interval and provide an inversion of this rotation.
  We show that the details of the hysteresis loops of our exchange-coupled
films can be described using the classical model of homogeneous magnetization
rotation of single uniaxial films and the configuration of observed domains.
The understanding of these features is crucial for applications (for MEMS or
microactuators) which benefit from the greatly enhanced sensitivity near the
point of magnetic saturation at the transverse applied field.
