The vision of CHIRON is to complement and, in the long term, replace CMOS by spin wave computing circuits.

The CHIRON objectives:

  • Development of magnetoelectric and multiferroic nanoresonators as spin wave transducers. 

  • Development of spin wave waveguides with sub-micrometre wavelengths. 

  • Demonstration of logic inverters as well as three-input majority gates based on the magnetoelectric and multiferroic transducers and waveguides.

  • Demonstration of frequency multiplexing in these devices.

  • Design of hybrid spin wave–CMOS circuits and benchmarking against standard CMOS using calibrated compact models of transducers and logic gates as well as interconnects.


Spin waves are particularly suited for the realization of compact interference-based majority gates, called Spin-Wave Majority Gate (SWMG). The basic structure is the inline SWMG, in which binary logic signals are encoded in the phases of the individual spin waves using phases of 0 and π as logic 0 and 1, respectively. Constructive or destructive interference leads then to an output wave with a phase that corresponds to the majority of the individual spin-wave phases. The amplitude of the output wave contains further information whether weak or strong majority is obtained.  
SWMG with electrical transducers Top

Our implementation will be based on Co40Fe40B20 and permalloy waveguides with widths down to 850 nm. 

Micromagnetic simulations for 850-nm-wide Co40Fe40B20 waveguides in the Damon-Eshbach geometry show the excitation of spin waves confined in the center of the waveguide.


Animations of the experimental magnetization dynamics in a SWMG with a 2.0 μm wide permalloy waveguide, imaged by time-resolved scanning transmission x-ray microscopy for different combinations of input phases: (π; π; π); (0; 0; π); (0; π; 0). The input phase combinations are indicated in the animations (details: Talmelli et al, Sci. Adv. 6(51), eabb4042 (2020)).


Animations of the magnetization dynamics in a SWMG with an 850 nm wide Co40Fe40B20 waveguide calculated by micromagnetic simulations for different combinations of input phases: (0; 0; 0); (π; 0; π). The input phase combinations are indicated in the animations. The complementary combinations (π; π; π) and (0; π; 0) can be obtained by shifting the time by half of a period.