Abstract:Reducing power dissipation is perhaps the most important challenge in complementary metal oxide semiconductor (CMOS) electronics. To support the required gate voltage modulation, it is usually necessary to supply the CMOS transistor with at least 0.5 V. Other logic families, however, such as ion channels, mechanical relays, and spin-based magnetic devices, incorporate collective behavior in their switching thus lowering the supply voltage. Collective phenomena such as the orientation of a ferromagnetic domain are additionally more stable against thermal fluctuations.
In this talk I will report on the fabrication and modeling of a promising instantiation of magnetic logic using current-induced domain wall motion. Information is stored in transverse domain walls in thin ferromagnetic wires, and read-out is performed by a magnetic tunnel junction. Device fabrication is done using electron-beam lithography and UHV sputter deposition. I will present results from modeling the device behavior in circuits, to demonstrate that the logic device satisfies all the important qualities of beyond-CMOS logic: it scales well with size, to low operating voltages in the range of 0.1 V and energies competitive to contemporary CMOS, and it acts as a non-volatile universal gate that can be successfully integrated into complex circuits. Additionally, it is compatible with CMOS since it uses charge as its input and output, and is comprised of cheap and readily available materials. I will show simulations of a clocked oscillator and find a switching time of 5.2 ns, and demonstrate the operation of a full adder circuit. The results show that magnetic domain wall based logic is a realistic contender to replace CMOS at the end of its roadmap.
Jean Anne Currivan (MIT)
2004-2008 B.A. Physics, B.A. Philosophy, University of California, Berkeley
Thesis under M. Hoogerland on quantum chaos in Rb87 Bose-Einstein Condensates
2009-Present Ph.D. Student, Harvard University
Research under C.A. Ross and M. Baldo at Massachusetts Institute of Technology on magnetic materials and domain wall based logic