Abstract: This talk will discuss some of the emerging device concepts in spintronics for energy-efficient memory-intensive computing and communications. We will first review recent progress and perspectives of voltage-controlled nonvolatile magnetic memory devices, which offer ultralow dynamic energy dissipation, as well as reduced standby power due to nonvolatile data retention and are uniquely suited to emerging memory-intensive computing paradigms. We will then discuss some of the implications of material and device-level advances of voltage-controlled magnetic tunnel junctions in the area of microwave detectors, which may be relevant to energy harvesting and communications in ultralow-power systems.
As a strategy to further reduce switching time and write energy, and enable deep scaling of magnetic random access memory (MRAM), we then examine devices based on antiferromagnetic materials. Spintronic devices based on antiferromagnetic (AFM) materials offer potential advantages over their ferromagnetic counterparts such as picosecond switching, high-density device arrays without inter-bit-dipole interactions, immunity to external magnetic fields, and generation of terahertz signals at the nanometer scale (i.e., THz nano-oscillators). Analogous to the case of ferromagnetic devices, AFM spintronic devices must achieve two main requirements: a reliable electrical method for reading the magnetic state of the AFM and an energy-efficient and scalable method to modify (i.e., write) its magnetic state. This talk will focus on the second requirement, describing recent progress in switching the Néel vector of an antiferromagnetic device by two methods: voltage-controlled modification of the interfacial magnetic anisotropy and current-induced spin-orbit torque.
Bio: Pedram Khalili is an associate professor of electrical and computer engineering at Northwestern University, where he is also a faculty member of the Applied Physics graduate program and Director of the Physical Electronics Research Laboratory. He has led multiple research programs on voltage-controlled MRAM, spin-transfer-torque MRAM, and nonvolatile spintronic logic, working with several major industry partners, which resulted in some of the fastest and most energy-efficient magnetic memories to date, from device-level to array-level prototypes.