Realization of spin-wave logic gates

Abstract

We demonstrate the functionality of spin-wave logic XNOR and NAND gates based on a MachZehnder type interferometer which has arms implemented as sections of ferrite film spin-wave waveguides. Logical input signals are applied to the gates by varying either the phase or the amplitude of the spin waves in the interferometer arms. This phase or amplitude variation is produced by Oersted fields of dc current pulses through conductors placed on the surface of the magnetic films.Although commonly used for data storage applications, there have been relatively few attempts to employ magnetic phenomena for performing logical operations. The suggested concepts include the control of domain wall movement [1], of magnetoresistance of individual magnetic elements [2], and of a magnetostatic field of a set of magnetic nanoelements [3]. Yet another concept is using spin-wave interferometers. It was discussed theoretically in Refs. [4,5,6], but there was only one experimental demonstration of spin wave logic gate functionality [7], where an one-input NOT gate was implemented in a interferometer-like geometry. In the present work we experimentally demonstrate the functionality of more complicated logic gates based on spin waves.The fabricated prototype of a XNOR logic gate is a direct extension of the NOT gate from Ref. [7] which was based on a Mach-Zehnder interferometer. For its implementation the reference interferometer arm of the NOT gate is replaced by an arm identical to the signal arm. Controlling phases accumulated by the spin waves in both arms allows one to perform the XNOR operation.Demonstrating the functionality of a NAND logic gate is a considerable step forward in the development of spin wave logic compared to the NOT and XNOR gates. Firstly because the NAND function belongs to a class of universal functions which means that combining NAND gates allows one to construct gates of other types. Secondly because for its implementation, we use here a new physical principle: direct control of spin wave amplitudes in the interferometer arms.Figure 1(b) shows the principle setup of an exclusive not OR (XNOR, also called logical equality) gate. It consists of two arms of a spin-wave Mach-Zehnder interferometer implemented as ferrite film structures. Spin waves are inserted in both arms using microstrip antennas connected to a common microwave pulse source, thus guaranteeing the same phase in both arms. The spin waves are phase-coherently detected using microstrip antenna detectors. The signals of both arms are brought to interference electronically. The phase accumulated by the spin waves on their paths through the two arms is controlled by applying dc currents I 1 and I 2 to the arms. Figure 1(a) shows phase inserted due to a current in an interferometer arm. One sees a linear dependence of the accumulated phase on the current. One also sees that the phase characteristics in both arms are identical.The currents I 1 and I 2 serve as logical inputs, where a logical zero is represented by I = 0 A and a logical one by the cur...

Strong asymmetry of microwave absorption by bilayer conducting ferromagnetic films in the microstrip-line based broadband ferromagnetic resonance

“…From the condition Z r << z 0 to the first order in Z r /z 0 from Eqs. (12)(13)(14)(15)(16)(17)(18)(19)(20) one obtains…”

“…This interest is largely due to the possibility of using spin waves to perform logic operations [15,16,17,18,19,20]. If necessary, the expressions we obtain can be easily extended to describe excitation of propagating spin waves following suggestions in Ref.…”

Optically reconfigurable magnetic materials

“…Periodic variation of the magnetic material's parameters allows the realization of magnonic crystals with novel properties not found in the unstructured material. For example, the dispersion relation of spin waves can be controlled to achieve new schemes for spin-wave-based computing [1][2][3][4][5][14][15][16][17] . The spin-wave dispersion relation depends on many parameters, such as the geometry of the spin-wave waveguide (film thickness and waveguide width), external magnetic field H ext , and saturation magnetization M S .…”

Угловые Зависимости Спектров Спин-Волнового Резонанса В Неоднородных Пленках С Орторомбической Анизотропией

“…Исследование особенностей спиновой динамки в ди-электрических магнитных пленках представляет несо-мненный научный и практический интерес, обусловлен-ный перспективами применения данных материалов в устройствах спинтроники и магнетоэлектроники [1][2][3]. Спектры спин-волнового резонанса (СВР) в многослой-ных пленках с однородными слоями, и в частности их угловые зависимости, изучены в работах [4][5][6].…”