Voltage-Reconfigurable Magnetic Invisibility: A New Concept for Data Security Based on Engineered Magnetoelectric Materials

Informations projet

REMINDS

N° de convention de subvention: 101054687

DOI

10.3030/101054687

Date de signature de la CE 18 Mai 2022

Date de début 1 Février 2023

Date de fin 31 Janvier 2029

Financé au titre de

• European Research Council (ERC)

Coût total

€ 2 499 940,00

Contribution de l’UE

€ 2 499 940,00

Coordonné par

UNIVERSITAT AUTONOMA DE BARCELONA
Spain

Periodic Reporting for period 1 - REMINDS (Voltage-Reconfigurable Magnetic Invisibility: A New Concept for Data Security Based on Engineered Magnetoelectric Materials)

Période du rapport: 2023-02-01 au 2025-07-31

Résumé du contexte et des objectifs généraux du projet

With the advent of Big Data, information is facing new, potentially more damaging, security threats. The current trend to enhance data protection is to use increasingly complex mathematical algorithms to encrypt information. This approach requires exponentially growing amounts of data, time and power resources. REMINDS proposes a radically new concept to boost data security: to act directly at material level, i.e. in the way information is stored. The project is built on the disruptive idea of using voltage to activate/deactivate magnetism and it tackles novel strategies to control the mutual interactions between materials of distinct characteristics. Neuromorphic-inspired layouts are being used to selectively apply these voltage protocols to specific memory units. This constitutes the basis of new energy-efficient proof-of-concept data protection designs whose working principle is tested at lab scale for potential applications in solid and flexible substrates. REMINDS is expected to revolutionize magnetoelectricity, exploiting voltage-programmable magnetism to an unprecedented extent and forging an entirely new paradigm in data security. Its outcomes will bring ground-breaking scientific contributions to the fields of magnetism, spintronics, piezotronics and flexible electronics, and may have a huge socio-economic impact.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

During the initial phase of the project, we focused on developing various magnetoelectric materials, primarily through sputtering. These include CoxMn1-xN and CoxFe1-xN compounds, where external voltage can trigger motion of N ions; FeRh, where voltage induces ferromagnetic–antiferromagnetic metamagnetic transitions; complex oxide materials where O ions migrate under voltage; several heterostructures interfaced with ferroelectric substrates (PMN-PT, PMN-PZT) where voltage-driven strain mediates changes in diverse magnetic properties; and magnetostrictive films and structures adjacent ferroelectric films to study multiferroic effects. Some of these materials have been patterned via optical lithography and e-beam lithography, allowing us to explore magnetoelectric phenomena in sub-micrometer-sized dots.

All samples have been structurally and compositionally characterized using a broad range of experimental techniques, including scanning/transmission electron microscopy, XMCD/PEEM, and scanning probe microscopy (MFM and PFM modes). Magnetoelectric measurements were conducted in situ using both liquid and solid electrolytes, with custom-made electrolytic cells adapted for MOKE and VSM devices.

A key focus has been the voltage-driven motion of O²⁻ and N³⁻ ions. We demonstrated that their diffusion can induce analog changes in magnetic properties, including ON-OFF switching of ferromagnetism, a crucial effect for data security applications. In some cases, this process mimics synaptic activity (potentiation/depression effects), presenting opportunities for neuromorphic computing. Particularly intriguing is the possibility of wireless magneto-ionics via bipolar electrochemistry. We have also made progress in light-controlled ferromagnetism.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

REMINDS has expanded magneto-ionics beyond conventional oxygen-based systems by incorporating and optimizing new materials in which voltage can trigger fast diffusion of N³⁻ ions, which tend to move forming planar migration fronts instead of irregular clusters. This effect has been extensively studied in ternary compounds such as CoxMn1-xN and CoxFe1-xN, using both liquid and solid-state magnetoelectric configurations in thin films and patterned structures.
Recently, in circular dots of 200 nm in diameter, taking advantage of the planar N³⁻ migration front, we have discovered a novel magnetic object—a "magneto-ionic vortex state" or "vortion". While sharing some similarities with conventional vortices, vortions exhibit distinctive, voltage-tunable changes in magnetization and coercivity, emulating some functionalities of biological synapses.

Another remarkable finding from REMINDS is that magneto-ionic effects can be induced without direct electrical contact with the sample. This wireless activation occurs through a phenomenon known as bipolar electrochemistry, which holds promising applications in data security and biomedicine.
Through REMINDS, we have recently established collaborations with Singulus Technologies (Germany) and SPIN-ION (France) to explore magneto-ionic effects in RKKY-based artificial antiferromagnets and investigate how ion irradiation can enhance magneto-ionics through defect engineering. Additionally, we are employing a rich variety of substrates to develop these technologies.

To support the commercialization of REMINDS' foundational research, an ERC Proof of Concept grant has been awarded, fostering the translation of these scientific advances into real-world applications.

REMINDS data security concept, incorporating voltage control of magnetism in interacting materials.