Abstract
Due to their topological protection and nanometric size, magnetic skyrmions are anticipated to form components of new high-density memory technologies. In metallic systems skyrmion manipulation is achieved easily under a low density electric current flow, although the inevitable thermal dissipation ultimately limits the energy efficacy of potential applications. On the other hand, a near dissipation-free skyrmion and skyrmion phase manipulation is expected by using electric \emph{fields}, thus meeting better the demands of an energy-conscious society. In this work on an insulating chiral magnet Cu$_{2}$OSeO$_{3}$ with magnetoelectric coupling, we use neutron scattering to demonstrate directly i) the creation of metastable skyrmion states over an extended range in magnetic field and temperature, and ii) the in-situ electric field-driven switching between topologically distinct phases; the skyrmion phase and a competing non-topological cone phase. For our accessible electric field range, the phase switching is achieved in a high temperature regime, and the remnant (E=0) metastable skyrmion state is thermally volatile with an exponential lifetime on hour timescales. Nevertheless, by taking advantage of the demonstrably longer-lived metastable skyrmion states at lower temperatures, a truly non-volatile and near dissipation-free topological phase change memory function is promised in magnetoelectric chiral magnets.
Highlights
Magnetic skyrmions are nanoscale spin vortexlike objects which hold clear promise for use in spintronics applications by virtue of their topological protection [1,3]
We focus our attention on the chiral magnet Cu2OSeO3 which has a dielectric constant r ∼ 6 [28] and a well-established ME coupling below Tc [24,28,29,30,31,32,33,34,35,36,37,38]
From data obtained on the same crystal reported in Ref. [41], the extents of the equilibrium skyrmion phases for E = 0 and under E = +5.0 V/μm are determined from μ0H -increasing scans performed in the μ0H ki geometry
Summary
Magnetic skyrmions are nanoscale spin vortexlike objects which hold clear promise for use in spintronics applications by virtue of their topological protection [1,3]. Insights obtained from studying Cu2OSeO3 can be anticipated to be of direct relevance to future applications at room temperature In this context, a detailed understanding of the E-field response of both equilibrium and metastable Bloch-type skyrmion states in the only available chiral cubic insulating system Cu2OSeO3 is of clear importance for the nascent research field of “skyrmionics.” recent theoretical expectation for the E-field-induced creation and annihilation of skyrmions in insulators [39,40], and the E-field control of skyrmion phase stability [41], motivate the present work which focuses on functionalities that are attractive for applications. By using a standard MEFC procedure, metastable skyrmion states are created that exist over an extended parameter space compared with the typically narrow extent of the equilibrium skyrmion phase This includes base T, and an extended range of applied magnetic field (μ0H ); see Fig. 1. By creating longer-lived remnant metastable states at lower T, we show chiral magnets promise potentially useful phase-change memory functionalities based on ME coupling that should exist in principle at room temperature
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
