  We investigate switching of magnetic tunnel junctions (MTJs) driven by the
thermal effect of the transport current through the junctions. The switching
occurs in a specially designed composite free layer, which acts as one of the
MTJ electrodes, and is due to a current-driven ferro-to-paramagnetic Curie
transition with the associated exchange decoupling within the free layer
leading to magnetic reversal. We simulate the current and heat propagation
through the device and show how heat focusing can be used to improve the power
efficiency. The Curie-switch MTJ demonstrated in this work has the advantage of
being highly tunable in terms of its operating temperature range, conveniently
to or just above room temperature, which can be of technological significance
and competitive with the known switching methods using spin-transfer torques.
