According to an example embodiment an MTJ unit is provided. The MTJ unit includes: a first MTJ comprising a first free layer, a first tunnel barrier layer and a first reference layer. The first MTJ is switchable between a parallel state and an anti-parallel state through spin-torque transfer (STT). The MTJ unit comprises a second MTJ arranged above the first MTJ and comprising, a second reference layer, a second tunnel barrier layer and a second free layer. The second MTJ is switchable between a parallel state and an anti-parallel state through STT. The MTJ unit comprises a pinning layer arranged between the first reference layer and the second reference layer and configured to fix a magnetization direction of the first reference layer and the second reference layer.