Abstract: A device and method for high speed metamagnetic resistive switching provides a metamagnetic phase transitioning (MPT) portion formed on a substrate between terminals. The MPT portion is tuned for temperature-responsive transitions between magnetic phases through a transition phase. The phases are delineated by phase boundaries each traversed at different critical temperatures depending on direction of traversal. The critical temperatures of each phase boundary are mutually offset by a hysteretic shift. The MPT portion is boosted across one phase boundary responsive to thermal actuation pulsed in a first direction to reach or exceed both critical temperatures of that phase boundary in the first direction, and boosted across the other phase boundary responsive to thermal actuation pulsed in a second direction to reach or exceed both critical temperatures of that phase boundary in the second direction. The electrical conduction path is thereby adjusted in resistivity for switching between ON and OFF states.