Topologically protected whirling magnetic textures could emerge as data carriers in nextgeneratio... more Topologically protected whirling magnetic textures could emerge as data carriers in nextgeneration post-Moore computing. Such textures are abundantly observed in ferromagnets (FMs); however, their antiferromagnetic (AFM) counterparts are expected to be even more relevant for device applications, as they promise ultra-fast, deflection-free dynamics whilst being robust against external fields. Unfortunately, they have remained elusive, hence identifying materials hosting such textures is key to developing this technology. Here, we present comprehensive micromagnetic and analytical models investigating topological textures in the broad material class of A-type antiferromagnets, specifically focusing on the prototypical case of α-Fe2O3-an emerging candidate for AFM spintronics. By exploiting a symmetry breaking interfacial Dzyaloshinskii-Moriya interaction (iDMI), it is possible to stabilize a wide topological family, including AFM (anti)merons and bimerons and the hitherto undiscovered AFM skyrmions. Whilst iDMI enforces homochirality and improves the stability of these textures, the widely tunable anisotropy and exchange interactions enable unprecedented control of their core dimensions. We then present a unifying framework to model the scaling of texture sizes based on a simple dimensional analysis. As the parameters required to host and tune homochiral AFM textures may be obtained by rational materials design of α-Fe2O3, it could emerge as a promising platform to initiate AFM topological spintronics. I.
In the quest for post-CMOS technologies, ferromagnetic skyrmions and their anti-particles have sh... more In the quest for post-CMOS technologies, ferromagnetic skyrmions and their anti-particles have shown great promise as topologically protected solitonic information carriers in memory-in-logic or neuromorphic devices. However, the presence of dipolar fields in ferromagnets, restricting the formation of ultra-small topological textures, and the deleterious skyrmion Hall effect when driven by spin torques have thus far inhibited their practical implementations. Antiferromagnetic analogues, which are predicted to demonstrate relativistic dynamics, fast deflection-free motion and size scaling have recently come into intense focus, but their experimental realizations in natural antiferromagnetic systems are yet to emerge. Here, we demonstrate a family of topological antiferromagnetic spin-textures in $\alpha$-Fe$_2$O$_3$ - an earth-abundant oxide insulator - capped with a Pt over-layer. By exploiting a first-order analogue of the Kibble-Zurek mechanism, we stabilize exotic merons-antimero...
In the quest for post-CMOS technologies, ferromagnetic skyrmions and their anti-particles have sh... more In the quest for post-CMOS technologies, ferromagnetic skyrmions and their anti-particles have shown great promise as topologically protected 1-8 solitonic information carriers in memoryin-logic or neuromorphic devices 1, 9-11. However, the presence of dipolar fields in ferromagnets, restricting the formation of ultra-small topological textures 3, 6, 8, 9, 12 , and the deleterious skyrmion Hall effect when driven by spin torques 9, 10, 12 have thus far inhibited their practical implementations. Antiferromagnetic analogues, which are predicted to demonstrate relativistic dynamics, fast deflection-free motion and size scaling have recently come into intense focus 9, 13-19 , but their experimental realizations in natural antiferromagnetic systems are yet to emerge. Here, we demonstrate a family of topological antiferromagnetic spin-textures in α-Fe 2 O 3-an earth-abundant oxide insulator-capped with a Pt over-layer. By exploiting a first-order analogue of the Kibble-Zurek mechanism 20, 21 , we stabilize exotic merons-antimerons (half-skyrmions 8), and bimerons 16, 22 , which can be erased by magnetic fields and regenerated by temperature cycling. These structures have characteristic sizes of the order ∼100 nm that
Topologically protected whirling magnetic textures could emerge as data carriers in nextgeneratio... more Topologically protected whirling magnetic textures could emerge as data carriers in nextgeneration post-Moore computing. Such textures are abundantly observed in ferromagnets (FMs); however, their antiferromagnetic (AFM) counterparts are expected to be even more relevant for device applications, as they promise ultra-fast, deflection-free dynamics whilst being robust against external fields. Unfortunately, they have remained elusive, hence identifying materials hosting such textures is key to developing this technology. Here, we present comprehensive micromagnetic and analytical models investigating topological textures in the broad material class of A-type antiferromagnets, specifically focusing on the prototypical case of α-Fe2O3-an emerging candidate for AFM spintronics. By exploiting a symmetry breaking interfacial Dzyaloshinskii-Moriya interaction (iDMI), it is possible to stabilize a wide topological family, including AFM (anti)merons and bimerons and the hitherto undiscovered AFM skyrmions. Whilst iDMI enforces homochirality and improves the stability of these textures, the widely tunable anisotropy and exchange interactions enable unprecedented control of their core dimensions. We then present a unifying framework to model the scaling of texture sizes based on a simple dimensional analysis. As the parameters required to host and tune homochiral AFM textures may be obtained by rational materials design of α-Fe2O3, it could emerge as a promising platform to initiate AFM topological spintronics. I.
In the quest for post-CMOS technologies, ferromagnetic skyrmions and their anti-particles have sh... more In the quest for post-CMOS technologies, ferromagnetic skyrmions and their anti-particles have shown great promise as topologically protected solitonic information carriers in memory-in-logic or neuromorphic devices. However, the presence of dipolar fields in ferromagnets, restricting the formation of ultra-small topological textures, and the deleterious skyrmion Hall effect when driven by spin torques have thus far inhibited their practical implementations. Antiferromagnetic analogues, which are predicted to demonstrate relativistic dynamics, fast deflection-free motion and size scaling have recently come into intense focus, but their experimental realizations in natural antiferromagnetic systems are yet to emerge. Here, we demonstrate a family of topological antiferromagnetic spin-textures in $\alpha$-Fe$_2$O$_3$ - an earth-abundant oxide insulator - capped with a Pt over-layer. By exploiting a first-order analogue of the Kibble-Zurek mechanism, we stabilize exotic merons-antimero...
In the quest for post-CMOS technologies, ferromagnetic skyrmions and their anti-particles have sh... more In the quest for post-CMOS technologies, ferromagnetic skyrmions and their anti-particles have shown great promise as topologically protected 1-8 solitonic information carriers in memoryin-logic or neuromorphic devices 1, 9-11. However, the presence of dipolar fields in ferromagnets, restricting the formation of ultra-small topological textures 3, 6, 8, 9, 12 , and the deleterious skyrmion Hall effect when driven by spin torques 9, 10, 12 have thus far inhibited their practical implementations. Antiferromagnetic analogues, which are predicted to demonstrate relativistic dynamics, fast deflection-free motion and size scaling have recently come into intense focus 9, 13-19 , but their experimental realizations in natural antiferromagnetic systems are yet to emerge. Here, we demonstrate a family of topological antiferromagnetic spin-textures in α-Fe 2 O 3-an earth-abundant oxide insulator-capped with a Pt over-layer. By exploiting a first-order analogue of the Kibble-Zurek mechanism 20, 21 , we stabilize exotic merons-antimerons (half-skyrmions 8), and bimerons 16, 22 , which can be erased by magnetic fields and regenerated by temperature cycling. These structures have characteristic sizes of the order ∼100 nm that
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Papers by Jack Harrison