In one aspect of the present invention, the semiconductor device is a bipolar magnetic junction transistor (MJT), and includes a first non-magnetic semiconductor layer, a second non-magnetic semiconductor layer, and a magnetic semiconductor layer. The first non-magnetic semiconductor layer has majority charge carriers of a first polarity. The second non-magnetic semiconductor layer is disposed adjacent to the first non-magnetic semiconductor layer such that a first junction is formed at a first interface region between the first non-magnetic semiconductor layer and the second non-magnetic semiconductor layer. The magnetic semiconductor layer has majority charge carriers of the first polarity, and is disposed adjacent to the second non-magnetic semiconductor layer such that a second junction is formed at a second interface region between the second non-magnetic semiconductor layer and the magnetic semiconductor layer.