Dynamic switching of the spin circulation in tapered magnetic nanodisks

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Abstract

Magnetic vortices are characterized by the sense of in-plane magnetization circulation and by the polarity of the vortex core. With each having two possible states, there are four possible stable magnetization configurations that can be utilized for a multibit memory cell. Dynamic control of vortex core polarity has been demonstrated using both alternating and pulsed magnetic fields and currents. Here, we show controlled dynamic switching of spin circulation in vortices using nanosecond field pulses by imaging the process with full-field soft X-ray transmission microscopy. The dynamic reversal process is controlled by far-from-equilibrium gyrotropic precession of the vortex core, and the reversal is achieved at significantly reduced field amplitudes when compared with static switching. We further show that both the field pulse amplitude and duration required for efficient circulation reversal can be controlled by appropriate selection of the disk geometry.

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Figure 1: Sample configuration.
Figure 2: MTXM images showing the switching of spin circulation in magnetic vortices by static magnetic fields and field pulses.
Figure 3: Conditions for static and dynamic annihilation of the vortex core.
Figure 4: Temporal evolution of dynamic annihilation of the vortex core.

Change history

  • 24 April 2013

    In the version of this Article originally published online, in the ninth paragraph, the word 'redundant' should not have appeared in the sentence"...are summarized in Table 1 and the minimum pulse durations are plotted in Fig. 3b (blue triangles) for 20-nm-thick disks". In the tenth paragraph, the formula s = RχB/(μ0MS) should have appeared as shown here. These errors have been corrected in all versions of the Article.

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Acknowledgements

The authors thank R. Descoteaux and O. Inac for technical help. The authors also thank M. Escobar and V. Lomakin for help with the FastMag simulations, R. Antoš for useful discussions and J. Sapan for editing the manuscript. The research at UCSD was supported by the research programs of the US Department of Energy (DOE), Office of Basic Energy Sciences (award #DE-SC0003678), and the research at CEITEC BUT by the European Regional Development Fund (CEITEC – CZ.1.05/1.1.00/02.0068) and the Grant Agency of the Czech Republic (project no. P102/12/P443). The operation of the X-ray microscope was supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the US DOE (contract no. DE-AC02-05-CH11231). Sample nanofabrication was supported by the company TESCAN.

Author information

V.U. and M.U. designed and planned the experiment. M.U. and L.H. fabricated the samples. V.U., M.U., J.S. and T.Š. performed the experiments, with help from M-Y.I., P.F., N.E. and J.J.K. V.U. and M.U. carried out the micromagnetic simulations, analysed the data and prepared the figures. E.E.F. was involved in experimental planning and analysis of the results. V.U. wrote the manuscript. All authors commented on the manuscript.

Correspondence to V. Uhlíř.

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Uhlíř, V., Urbánek, M., Hladík, L. et al. Dynamic switching of the spin circulation in tapered magnetic nanodisks. Nature Nanotech 8, 341–346 (2013) doi:10.1038/nnano.2013.66

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