APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022;
Chicago
Session G53: Magnetic Thin Films: Novel Synthesis/Multiferroics
11:30 AM–2:30 PM,
Tuesday, March 15, 2022
Room: McCormick Place W-475B
Sponsoring
Unit:
GMAG
Chair: Margaret Kane, Stanford
Abstract: G53.00001 : Reversible ionic control of antiferromagnetic anisotropy
11:30 AM–11:42 AM
Abstract
Presenter:
Hariom K Jani
(Natl Univ of Singapore)
Author:
Hariom K Jani
(Natl Univ of Singapore)
Antiferromagnets (AFMs) are a ubiquitous class of magnetic materials, holding the promise of low-dissipation spintronic computing devices that can display ultra-fast switching, density scaling and robustness against stray fields. However, magnetic sublattice compensation makes it difficult to detect and control AFM textures in a reversible and scalable manner via standard techniques. We overcame this limitation by developing a novel ionic approach to reversibly tailor AFM anisotropy. We focussed on the earth-abundant AFM α-Fe2O3, which exhibits a spin-reorientation (Morin) transition between in-plane and out-of-plane configurations. Developing reversible control of AFM anisotropy in α-Fe2O3 is important for prospects in topological spintronics and magnonics. Regarding the former, I will discuss our recent results where the Morin transition was exploited to stabilize a wide family of exotic AFM topological textures - half-skyrmions and bimerons - at room temperature. These topological textures have core sizes (of ≈ 100 nm) and can be scaled further with anisotropy tuning. In this context, I will discuss our findings on ionic control of antiferromagnetism in epitaxial α-Fe2O3 films. The catalytic-spillover process employs Pt nano-structures to hydrogenate the AFM films, thereby, driving pronounced changes in the anisotropy, Néel vector orientation and canted magnetism via local charge-doping. As H ions are very small and light, they can be added/removed from the host lattice, without significantly disturbing the overall structure. This allows our approach to be stable yet reversible. Tailoring our work for future applications, we demonstrated reversible control of the room-temperature AFM-state by doping/expelling H ions in Rh-substituted α-Fe2O3. I will conclude by presenting the wider implications of our work, such as how AFM-state control could eventually be realized electrically and translated to a wider variety of AFMs (e.g. orthoferrites, orthochromites).