Embodiments are directed to STT MRAM devices. One embodiment of an STT MRAM device includes a reference layer, a tunnel barrier layer, a free layer and one or more conductive vias. The reference layer is configured to have a fixed magnetic moment. In addition, the tunnel barrier layer is configured to enable electrons to tunnel between the reference layer and the free layer through the tunnel barrier layer. The free layer is disposed beneath the tunnel barrier layer and is configured to have an adaptable magnetic moment for the storage of data. The conductive via is disposed beneath the free layer and is connected to an electrode. Further, the conductive via has a width that is smaller than a width of the free layer such that a width of an active STT area for the storage of data in the free layer is defined by the width of the conductive via.