  Electrical current-induced deterministic magnetization switching in a
magnetic multilayer structure without external magnetic field is realized by
utilizing interlayer exchange coupling. Two ferromagnetic Co layers, with
in-plane and out-of-plane anisotropy respectively, are separated by a spacer Ta
layer, which plays a dual role of inducing antiferromagnetic interlayer
coupling, and contributing to the current-induced effective magnetic field
through the spin Hall effect. The current-induced magnetization switching
behavior can be tuned by pre-magnetizing the in-plane Co layer. The
antiferromagnetic exchange coupling field increases with decreasing thickness
of the Ta layer, reaching 630+-5 Oe for a Ta thickness of 1.5nm. The magnitude
of the current-induced perpendicular effective magnetic field from spin-orbit
torque is 9.2 Oe/(107Acm-2). The large spin Hall angle of Ta, opposite in sign
to that of Pt, results in a low critical current density of 9*10^6A/cm^2. This
approach is promising for the electrical switching of magnetic memory elements
without external magnetic field.
