Northwestern University

Researchers from Northwestern University, led by Prof. Pedram Khalili, report the first all-antiferromagnetic tunnel junction (ATJ) devices with both electrical switching and electrical readout of the antiferromagnetic state. The researchers observed a large room-temperature tunneling magnetoresistance effect that is comparable in size to conventional ferromagnet-based tunnel junctions. 

To create the new devices, the researchers used sputtering to deposit the device films on conventional silicon wafers. The films are compatible with established semiconductor manufacturing processes. 

Researchers from Northwestern University, in collaboration with researchers from China, Italy and France, developed a new SOT-MRAM device structure that enables deterministic switching without any need for bias magnetic fields.

The new approach, unlike most earlier methods, can be scaled to large wafers with good uniformity, since it doesn't rely on having a structural asymmetry in the device. SOT-MRAM devices based on this structure could be faster and more energy-efficient than current designs.

Researchers from Northwestern University developed a new method of building artificial neural networks using MRAM-based stochastic computing units. The researchers say that this design could enable AI devices that are highly energy efficient.

Embedded MRAM technologies are being adopted at major foundries, which enable the use of these technologies for unconventional computing architectures that use the stochasticity of MRAM cells (rather than their nonvolatility), to perform energy-efficient computing operations. MRAM cells exhibit stochastic switching characteristics, which is a challenge for reliable memory devices. But for neural networks, this can be taken advantage of if the MTJs are appropriately designed.

Researchers from Northwestern University and the University of Messina in Italy developed a new MRAM memory device composed of antiferromagnetic materials, which could be beneficial for use in AI systems and cryptocurrency mining.

Antiferromagnetic materials (AFM), offer inherently faster dynamics than ferromagnetic materials (FM), have no macroscopic magnetic poles and can be scaled much better. AFM-based memory cannot be erased with external magnetic fields which could prove to be a major security advantage.

Researchers from Northwestern University suggest building STT-MRAM devices from antiferromagnetic materials - as opposed to the currently-used ferromagnetic ones. The researchers say that these materials will enable higher-density devices that feature high speed writing with low currents.

Antiferromagnetic materials are magnetically ordered at the microscopic scale, but not at the macroscopic scale. This means that there is no magnetic force between adjacent bits in MRAM cells built from these materials - which means you can pack them very close together.