Programmable Input for Nanomagnetic Logic Devices

Abstract

Abstract.A programmable magnetic input, based on the magnetic interaction of a soft and hard magnetic layer is presented for the first time. Therefore, a single-domain Co/Pt nanomagnet is placed on top of one end of a permalloy bar, separated by a thin dielectric layer. The permalloy bar of the introduced input structure is magnetized by weak easy-axis in-plane fields. Acting like a 'magnetic amplifier', the generated fringing fields of the permalloy pole are strong enough to control the magnetization of the superimposed Co/Pt nanomagnets, which have high crystalline perpendicular magnetic anisotropy. This magnetostatic interaction results in a shift of the hysteresis curve of the Co/Pt nanomagnet, measured by magneto-optical Kerr microscopy. The Co/Pt nanomagnet is fixed by the fringing field of the permalloy and thereby not affected by the magnetic power clock of the Nanomagnetic Logic system. MFM measurements verify the functionality of the programmable magnetic input structure. The fringing fields are extracted from micromagnetic simulations and are in good agreement with experimental results. The introduced input structure enables switching the logic functionality of the majority gate from NAND to NOR during runtime, offering programmable Nanomagnetic Logic.

Nanomagnetic logic based runtime Reconfigurable area efficient and high speed adder design methodology

“…P1: Different aspect ratio nanomagnets have varied metastable logic states against their preferred anisotropy. P2: To facilitate a state transition among the varied length nanomagnets, it requires variation in the external clocking field applied (increasing/decreasing field) [24][25][26].…”

“…Subsequently, a full adder architecture has been proposed using pipelined three input magnets [20]. Along side, researchers focused on the shape (S) engineering [21][22][23], programmable inputs [23][24][25][26][27][28], positional (P) anisotropy [29] and SP hybrid anisotropy [30] of the nanomagnets pertaining towards enhanced area optimization and robustness. Adder implementation using slanted edge inputs [31] and 45°positioned [32] nanomagnets have been demonstrated.…”

Dipole coupled magnetic quantum-dot cellular automata-based efficient approximate nanomagnetic subtractor and adder design approach

“…To realize this NML on-chip, Alam et al [13] demonstrated the clocking scheme. Subsequently, further optimizations have been reported by exploiting the shape (S) [14][15][16], positional (P) [17,18] anisotropy and the input programmability of the majority logic gate [19][20][21][22]. As part of the arithmetic circuit design using MQCA, Varga et al and Li et al proposed the full adder designs [23][24][25].…”

1-Bit Full Adder in Perpendicular Nanomagnetic Logic using a Novel 5-Input Majority Gate

“…Information is processed by complex circuits providing non-volatile logic operation using majority gates and inverters connected by wires [10]. Crossing of magnetic signals is achieved by detouring through additional functional layers [11] and logic gates can be programed during runtime [12]. Current wires [13] and spin transfer torque (STT) devices [14] are envisioned as I/O elements for electrical circuitry integration.…”