Spin switch devices with voltage controlled magnetism in ultra-low power usage applications are disclosed. The spin switch devices may be configured to provide ultra-low power and ultra-high speed switching by directly controlling drain or gate electron spins via electric field induced magnetic anisotropy tuned with finite gate voltage. A lateral spin switch with voltage controlled magnetic drain is placed in an “OFF” or an “ON” state by controlling the gate voltage to be equal to 0 or greater than 0 volts respectively. A vertical spin switch with voltage controlled magnetic gate is placed in an “OFF” or an “ON” state by controlling a value of the gate voltage to be less than a threshold voltage or greater than the threshold voltage respectively. A voltage controlled complementary switch provides a very large gain by controlling a value of the gate voltage to be equal to 0 volts.