Ferroionic inversion of spin polarization in a spin-memristor

Abstract

Magnetoelectric coupling in artificial multiferroic interfaces can be drastically affected by the switching of oxygen vacancies and by the inversion of the ferroelectric polarization. Disentangling both effects is of major importance toward exploiting these effects in practical spintronic or spinorbitronic devices. We report on the independent control of ferroelectric and oxygen vacancy switching in multiferroic tunnel junctions with a La0.7Sr0.3MnO3 bottom electrode, a BaTiO3 ferroelectric barrier, and a Ni top electrode. We show that the concurrence of interface oxidation and ferroelectric switching allows for the controlled inversion of the interface spin polarization. Moreover, we show the possibility of a spin-memristor where the controlled oxidation of the interface allows for a continuum of memresistance states in the tunneling magnetoresistance. These results signal interesting new avenues toward neuromorphic devices where, as in practical neurons, the electronic response is controlled by electrochemical degrees of freedom.

From Spintronic Memristors to Quantum Computing

“…The magnetoelectric coupling in the multiferroic interface is affected by oxygen vacancy and ferroelectric polarization reversal, so it is meaningful to add multiferroic materials in electronic devices to realize the STT effect. Recently, Rouco et al reported the multiferroic tunnel junctions using La 0.7 Sr 0.3 MnO 3 as the bottom electrode, BaTiO 3 ferroelectric barrier as the functional layer, and Ni as the top electrode, in which the ferroelectric switching and oxygen vacancy was independently controlled . This work shows that interface oxidation and ferroelectric switching can simultaneously control the change of interface spin polarization and further indicates the possibility of preparing a spintronic memristor.…”

“…(g) Details of the TMR switching. Panels a–g reproduced with permission from ref . Copyright 2021 AIP Publishing.…”

Electrolyte Gated Synaptic Transistor based on an Ultra‐Thin Film of La0.7Sr0.3MnO3

“…[36,37] In particular, oxide thin films and interfaces can be drastically affected by the amount and profile of oxygen vacancies. [38][39][40][41] A prototypical example can be found in the La 1-x Sr x MnO 3 system and, more specifically, in La 0.7 Sr 0.3 MnO 3 (LSMO), a half-metal with a perovskite structure characterized by a strong coupling between lattice, charge, and spin, providing a number of different degrees of freedom to externally manipulate its electronic properties including charge, orbital, spin, and magnetic ordering phenomena. [42][43][44][45] Thin LSMO films exhibit an insulatormetal transition whose transition temperature can be controlled with thickness, [46] strain, [47] and stoichiometry.…”

Voltage-Controlled ON–OFF-Switching of Magnetoresistance in FeOx/Fe/Au Aerogel Networks

“…In Fe 3 O 4 films gated via a solid Li 4 SiO 4 electrolyte, voltage-tunable MR was achieved by reversible Li + insertion and an associated reduction of Fe 3+ to Fe 2+ , which modulates the spin polarization . Furthermore, voltage-induced modulation of tunneling magnetoresistance (TMR) in thin film magnetic tunnel junctions has been attributed to magneto-ionic effects involving O 2– or Li + ions. − In GdO x thin film stripes, voltage-tunable MR is related to O 2– ion migration . Recently, we demonstrated oxygen-based magneto-ionic control of the magnitude and the sign of MR in Fe 3 O 4 /Fe nanocomposite thin film stripes upon liquid electrolyte gating in an alkaline solution …”