Reconfigurable logic with single magnetorestistive elements

Abstract

PACS 85.70.Ay, 87.75.DdThe logic gates of present computers are based on transistors and increasing the computational power means increasing their integration density. Among others, the utilization of magnetism is a promising alternative. A new concept for a magnetic logic gate is discussed, which is based on a single magnetoresistive element addressable by three independent input lines. Each of these gates can represent one out of at least ten logic functions, among them the four elementary functions AND, OR, NAND and NOR, the two more complex funtions XOR and XNOR as well as two reversible ones, CNOT and CCNOT. The functionality of the proposed gate can be pre-programmed with processor speed, its output is non-volatile. As a first application, which takes full advantage of the reprogrammability and non-volatility of the logic elements, a compact design of a magnetic full adder is discussed.

From ferro- to antiferromagnetism via exchange-striction of MnAs/GaAs(001)

“…The experimental geometry of the latter two series actually is employed in magnetostriction (λ) measurements with a CBM, where the change of the equilibrium lattice spacings upon varying the film magnetization gives rise to magnetostrictive stress (here by rotating the film magnetization (M ) from the easy a-axis to the b-or c-axes, respectively). In accordance with a recent study [23], the magnetostrictive stress of the pure α-phase (i.e., at 10 • C in fig. 2) is small, yielding magnetoelastic coupling constants of the same order of magnitude as for the transition metals Fe, Co, and Ni.…”

“…For H c the magnetocrystalline energy of 0.15 meV/MnAs [29] is about half of the Zeeman energy, which explains the observed reduction of the field-induced α-MnAs fraction compared with the other geometries. We remark that the magnetoelastic energy of 0.027 meV calculated with the coupling constants of α-MnAs [23] plays only a minor role. Obviously, the anisotropy observed by our directiondependent experiments is the result of the magnetocrystalline anisotropy of α-MnAs.…”

Sixteen logic functions in a single electronic circuit

“…Some of these using magnetic materials. 20,21 In Bae et al 22 they obtain 14 out 16 boolean functions with magnetic tunnel junction gates using magnetic field properties and spin torque of the circuit input terminal as physical variables, functions XOR and XNOR, are obtained by cascading these devices to obtain the full 16 function set. Matsuno et al 23 proposed a reconfigurable circuit using a magnetic transistor called spin MOSFET; a similar concept was introduced recently by Luo et al, 24 where they generate basic logic gates using spinning electromagnetic nanostructures called skyrmions.…”

“…An interesting topic is the generation of basic logic gates with reconfiguration properties. Some of these using magnetic materials 20,21 . In Bae et al 22 they obtain 14 out 16 boolean functions with magnetic tunnel junction gates using magnetic field properties and spin torque of the circuit input terminal as physical variables, functions XOR and XNOR, are obtained by cascading these devices to obtain the full 16 function set.…”