Ultrafast and Ultralow‐Power Voltage‐Dominated Magnetic Logic

Abstract

Conventional computers are built on devices combining a volatile silicon-based complementary metalÀoxideÀsemiconductor (CMOS) logic processor with external nonvolatile memory. Frequent communication between the logic processor and the memory results in low speed and high power consumption [1] (the von Neumann performance bottleneck). A promising approach to address this issue is combining reconfigurable logic and built-in nonvolatile memory through the use of magnetic logic [2] , such as magnetic field-controlled logic, [3] electric field-controlled magnetic logic, [4][5][6][7] magnetic domainwall (DW) logic, [8][9][10][11] magnetic logic based on magnetic tunnel junctions (MTJs), [12,13] or the anomalous Hall effect (AHE). [14,15] All of these approaches, however, suffer from certain limitations.Diode-assisted geometry-enhanced low-magnetic-field magnetoresistance in silicon can be used to perform basic Boolean logic operations. The large required magnetic field (0.15 T) limits, however, application of this approach. Magnetic switching can also be controlled using a ferromagnetic/ferroelectric structure [5] or electrical gating of the oxygen level, [7] forming electric field-controlled magnetic logic. However, the long times and limited suitability for cascading also make this approach unsuitable for practical applications. [6,16] Magnetic DW logic-encoded data and processed logic or memristive operations with DWs propagating through complex networks of nanowires under the action of an externally applied magnetic field or current have also been investigated. [8,10] For magnetic logic based on MTJs and Schottky diode-enhanced MTJs, basic logic and arithmetic operations have also been implemented. [3,12,13] However, the power demand for magnetic DW logic and MTJbased logic is determined by the critical current for magnetic switching, as the current in the logic operation is used to drive directly magnetic switching. A DW logic of 1 μm in size has switching time of 6.25 ns and power consumption of 20.4 pJ, [10] while magnetic logic based on a 40 nm MTJ has a switching time of 1.31 ns and power consumption of 49.6 pJ. [17] Luo et. al proposed a form of magnetic logic by coupling the AHE and current-controlled negative differential resistance, thereby realizing in-memory computing. [15] This device has a long switching time of %100 ns, arising from the internal turn-on properties of current-controlled negative differential resisitance. To address this problem, Pu et. al replaced the current-controlled negative differential resisitance with insulator-to-metal transition materials, thereby achieving a reduction in switching time to 7.5 ns. [14] However, in these devices, the logic output is in the form of the current, and as such it is difficult to perform complex logic operations via cascading. In addition, as the turn-on resistance of current-controlled negative resistance components is large, and the current required for logic operations is large, the switching time is still relatively long, and the power consu...