  It is shown that magnetic states and field-driven reorientation transitions
in synthetic antiferromagnets crucially depend on contributions of higher-order
anisotropies. A phenomenological macrospin model is derived to describe the
magnetic states of two antiferromagnetically coupled magnetic thin film
elements. The calculated phase diagrams show that magnetic states with
out-of-plane magnetization, symmetric escaped spin-flop phases, exist in a
broad range of the applied magnetic field. Due to the formation of such states
and concomitant multidomain patterns, the switching processes in toggle
magnetic random access memory devices (MRAM) can radically deviate from
predictions within oversimplified models.
