PHOTOTHERMAG - Nanomagnet logic via photothermal excitation of nanomagnetic networks

Nanomagnet logic is considered a promising future computational technology, under continuous development all over the world, which combines data storage and processing using magnetic phenomena, like dipolar interactions and magnetic frustration, at the nanoscale. The objectives of this project are: i) to advance the knowledge of the physics generating the vast phenomenology occurring in networks of dipolar interacting magnetic nanostructures, in particular in networks implementing magnetic frustration (the so-called artificial Spin Ices, ASIs); ii) to establish a close relationship between this key scientific area and the intense technical research targeting the development of a reliable nanomagnet logic technology to address challenges related to "economy and digital society". These objectives will be pursued using nanotechnology and nano-photonics as key enabling technologies for the design and fabrication of magnetic metamaterials with optical activation and control of magnetic dipolar interaction and frustration phenomena. From the fundamental viewpoint, this research will open new views to the understanding and control of the magnetic behavior arising from frustration. Moreover, the technical approaches and the new understanding generated, will enable novel and more efficient (ultralow power) device concepts for nanomagnet logic with applications to information processing.

Regarding the latter aspect, present implementations of nanomagnet logic lack of reliability and this hindered its practical application. Very recently, it was shown that higher reliability can be achieved using networks of dipolar-interacting nanomagnets thermally activated. However, current approaches require a bulky heating system that: i) does not allow for discriminative heating of selected parts of a device (where the storage/computation has to take place), preventing the scalability and the possibility of integration with other technologies (e.g., CMOS); ii) is slow (typically on the timescale of hours); iii) is very inefficient in terms of energy consumption.

In this project we will build on our previous well-established experience with the design and fabrication of nanomagnet networks and plasmonics, to implement, investigate, and optimize the thermo-plasmonic effect for the optical thermal activation of nanomagnet networks. In short, we will nanofabricate hybrid nanostructures comprising magnetic and plasmonic parts, to efficiently harvest electromagnetic radiation via excitation of localized plasmons and exploit the consequent heat produced inside the nanostructures for their thermal activation. The main advantages of this approach as compared to those used so far are: i) it is contact-less; ii) it is highly discriminative with a control of heating generation in areas down to 1 square micron (diffraction limited); iii) photo-heating can be generated at arbitrary speed down to the sub-ns timescale.
From the one side, we will focus on the use of this novel approach for a deeper investigation of the still not fully understood intriguing physic phenomena occurring in ASIs. From the other side, we will explore a new concept of nanomagnetic logic devices based on opto- thermal activation of networks implementing both conventional ports for binary logic and more complex ASI-like networks exploiting magnetic frustration for the implementation of neuromorphic/stochastic logic schemes, for low-power data transfer and computation.

This project has been funded by RTI2018-094881-B-100 / MCIN/ AEI /10.13039/501100011033/ FEDER UE, Una manera de hacer Europa