A magnetic solid state device is disclosed. The magnetic solid state device includes a substrate and a topological insulator deposited on top of the substrate. The magnetic solid state device also includes a first perpendicular magnetic anisotropy (PMA) bit having a reference PMA layer located on the topological insulator, and a second PMA bit having a free PMA layer located on the topological insulator. A gate contact is utilized to receive various predetermined voltages for controlling the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between the reference PMA layer in the first PMA bit and the free PMA layer in the second PMA bit.