Device and method for high speed metamagnetic resistive switching

A two terminal switching device having high speed metamagnetic resistive switching between predetermined ON and OFF states for memory, comprising:

• a substrate;
• first and second terminals formed on said substrate;
• and,
• at least one metamagnetic phase transitioning (MPT) portion formed on said substrate, said MPT portion being formed of a metallic material and coupled to said first and second terminals to define an electrical conduction path in resistivity adjustable manner therebetween;
• wherein said MPT portion is selectively tuned for temperature-responsive bidirectional transitions in phase between antiferromagnetic (AFM) and ferromagnetic (FM) phases through an intermediate phase, a first phase boundary being defined between the AFM phase and the intermediate phase and a second phase boundary between the intermediate phase and the FM phase, the first and second phase boundaries each being traversed at different critical temperatures depending on direction of traversal, the different critical temperatures for each of the first and second phase boundaries being mutually offset by a hysteretic shift;
• wherein said MPT portion is driven in magnetic phase between the intermediate and FM phases to switch the electrical conduction path in resistivity from the OFF state to the ON state responsive to pulsed energization for raising said MPT portion in temperature up to at least the higher of the critical temperatures for the second boundary, said MPT portion being driven in magnetic phase between the intermediate and AFM phases to switch the electrical conduction path in resistivity from the ON state to the OFF state responsive to pulsed energization for lowering said MPT portion in temperature down to at least the lower of the critical temperatures for the first boundary;
• and,
• wherein the pulsed energization is applied across said first and second terminals, the pulsed energization being adaptively tuned in amplitude to define separately adjusted peak amplitudes in opposing directions relative to a predetermined baseline amplitude for raising and lowering the temperature of said MPT portion, said MPT portion at the predetermined baseline amplitude being biased to the intermediate phase, whereby the peak amplitudes may be different in the opposing directions depending on the predetermined baseline amplitude.

A method for high speed metamagnetic resistive switching between predetermined ON and OFF states for memory, comprising:

• establishing a substrate;
• establishing first and second terminals on said substrate;
• forming at least one metamagnetic phase transitioning (MPT) portion on said substrate, said MPT portion being coupled to said first and second terminals to define an electrical conduction path in resistivity adjustable manner therebetween;
• selectively tuning said MPT portion for temperature-responsive bidirectional transitions in phase between antiferromagnetic (AFM) and ferromagnetic (FM) phases through an intermediate phase, said selective tuning includes:
• defining first and second phase boundaries between the intermediate phase and the AFM and FM phases respectively;
• and,
• defining for each of the first and second phase boundaries different critical temperatures for traversal depending on direction of traversal, the different critical temperatures for each of the first and second phase boundaries being mutually offset by a hysteretic shift;
• boosting said MPT portion in magnetic phase across the first phase boundary responsive to thermal actuation pulsed in a first direction to reach or exceed both the critical temperatures of the first phase boundary in the first direction;
• and,
• boosting said MPT portion in magnetic phase across the second phase boundary responsive to thermal actuation pulsed in a second direction to reach or exceed both the critical temperatures of the second phase boundary in the second direction;
• wherein the pulsed thermal actuation includes pulsed energization applied across said first and second terminals, the pulsed energization being adaptively tuned in amplitude to define separately adjusted peak amplitudes in the first and second directions relative to a predetermined baseline amplitude, said MPT portion at the predetermined baseline amplitude being biased to the intermediate phase, whereby the peak amplitudes may be different in the first and second directions depending on the predetermined baseline amplitude;
• the electrical conduction path of said MPT portion being thereby adjusted in resistivity for switching between the ON and OFF states.