We investigated magnetic tunnel junction (MTJ)-based circuit that allows direct communication between elements without intermediate sensing amplifiers. Two- and three-input circuits that consist of two and three MTJs connected in parallel, respectively, were fabricated and are compared. The direct communication is realized by connecting the output in series with the input and applying voltage across the series connections. The logic circuit relies on the fact that a change in resistance at the input modulates the voltage that is needed to supply the critical current for spin-transfer torque switching the output. The change in the resistance at the input resulted in a voltage swing of 50-200 mV and 250-300 mV for the closest input states for the three and two input designs, respectively. The two input logic gate realizes the AND, NAND, NOR, and OR logic functions. The three-input logic function realizes the majority, AND, NAND, NOR, and OR logic operations.
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ACKNOWLEDGMENT This work was supported in part by the MRSEC Program of the National Science Foundation (NSF) under Award DMR-0212302 and Award DMR-0819885, and NSF ECCS (0702264).
- Magnetic logic
- magnetic tunnel junction (MTJ)
- spin logic
- spin-polarized current
- spin-torque transfer (STT)