Inductively Coupled Circuits with Spin Wave Bus for Information Processing

TL;DR

This paper introduces a novel wireless logic device interconnection method using spin waves in ferromagnetic films, offering a charge-free, controllable, and potentially more functional alternative to traditional transistor-based circuits.

Contribution

It presents experimental demonstration of inductive coupling via spin waves in ferromagnetic films and models the performance and control of logic circuits with a spin wave bus.

Findings

Successful inductive coupling at room temperature in NiFe and CoFe films

Numerical models show controllable switching of spin wave-based logic cells

Potential for wireless read-in/read-out and enhanced logic functionalities

Abstract

We describe a new approach to logic devices interconnection by the inductive coupling via a ferromagnetic film. The information among the distant devices is transmitted in a wireless manner via a magnetic field produced by spin waves propagating in the ferromagnetic film, referred to as the spin wave bus. As an alternative approach to the transistor-based architecture, logic circuits with spin wave bus do not use charge as an information carrier. A bit of information can be encoded into the phase or the amplitude of the spin wave signal. We present experimental data demonstrating inductive coupling through the 100nm thick NiFe and CoFe films at room temperature. The performance of logic circuits with spin wave bus is illustrated by numerical modeling based on the experimental data. Potentially, logic circuits with spin wave bus may resolve the interconnect problem and provide "wireless" read-in and read-out. Another expected benefit is in the enhanced logic functionality. A set of NOT, AND, and OR logic gates can be realized in one device structure. The coupling between the circuits and the spin wave bus can be controlled. We present the results of numerical simulations showing the controllable switching of a bi-stable logic cell inductively coupled to the spin wave bus. The shortcomings and limitations of circuits with spin wave bus are also discussed.