The free layer in a magneto-resistive memory element is stabilized through being pinned by an antiferromagnetic layer. A control valve layer provides exchange coupling between this antiferromagnetic layer and the free layer. When writing data into the free layer, the control valve layer is heated above its curie point thereby temporarily uncoupling the free layer from said antiferromagnetic layer. Once the control valve cools, the free layer magnetization is once again pinned by the antiferromagnetic layer.