ABSTRACT: Magnetic skyrmions are topological objects with swirling spin structure that carry topological charge and Berry phase in real space [1-2]. Skyrmions are appealing for application in spintronics as they can be driven by electrical currents with ultralow density. Typically, skyrmions emerge from the Dzyaloshinskii–Moriya interaction (DMI) in a finite magnetic field, at low temperature [1-2]. For practical applications, efforts have been made to extend the phase diagram of stable existence of skyrmions [3-5]. Alternatively, a growing group of artificially designed magnetic superstructures allowing for the existence of skyrmions without the need of a microscopically built-in DMI mechanism, which, however, compromise the mobility of skyrmions [6-8]. Here, we present a novel approach of building on the advantages of both the natural and the artificial skyrmion materials by patterning arrays of magnetic nano-disks on top of thin films with DMI. And we denote the emerging novel material as hybrid magnetic skyrmions (HMS). This type of HMS has a significantly broader domain of existence on the phase diagram without loss of mobility and can suppress the skyrmion Hall effect substantially. We further demonstrate the concept of HMS racetrack memory by creating isolated skyrmions via current pulses and driving them by a continuous current at the speed up to 850 m/s, which is around 2 times of the speed of the skyrmion with DMI only .
Roszler, A. N. Bogdanov and C. Pfleiderer, Nature 442, 797 (2006).
X. Z. Yu, Y. Onose, N. Kanazawa, J. H. Park, J. H. Han, Y. Matsui, N. Nagaosa and Y. Tokura, Nature 465, 901 (2010).
Y. Tokunaga, X. Z. Yu, J. S. White, H. M. Ronnow, D. Morikawa, Y. Taguchi and Y. Tokura, Nat. Commun. 6, 7638 (2015).
W. Jiang, P. Upadhyaya, W. Zhang, G. Yu, M. B. Jungfleisch, F. Y. Fradin, J. E. Pearson, Y. Tserkovnyak, K. L. Wang, O. Heinonen, S. G. E. te Velthuis and A. Hoffmann, Science 349, 283 (2015).
S. Woo, K. Litzius, B. Kruger, M.-Y. Im, L. Caretta, K. Richter, M. Mann, A. Krone, R. M. Reeve, M. Weigand, P. Agrawal, I. Lemesh, M.-A. Mawass, P. Fischer, M. Klaui and G. S. D. Beach, Nat. Mater. 15, 501 (2016).
L. Sun, R. X. Cao, B. F. Miao, Z. Feng, B. You, D. Wu, W. Zhang, A. Hu and H. F. Ding, Phys. Rev. Lett. 110, 167201 (2013).
Y. Y. Dai, H. Wang, P. Tao, T. Yang, W. J. Ren and Z. D. Zhang, Phys. Rev. B 88, 054403 (2013).
B. F. Miao, L. Sun, Y. W. Wu, X. D. Tao, X. Xiong, Y. Wen, R. X. Cao, P. Wang, D. Wu, Q. F. Zhan, B. You, J. Du, R. W. Li and H. F. Ding, Phys. Rev. B 90, 174411 (2014).
H. Z. Wu, B. F. Miao, L. Sun , D. Wu, and H. F. Ding, 95, 174416 (2017).
BIOGRAPHY: 1991-1995, B. Sc. at Tianjin University, China.
1995-1998, M. Sc. at Fudan University, China.
1998-2001, Ph. D. at Martin-Luther University, Germany.
2002-2005, postdoctor at Argonne National Lab. USA
Since 2006, Full Professor, School of Physics, Nanjing University, China, Principle investigator of Low Dimensional Magnetism group.
Main research interests: Low dimensional magnetism and spintronics.
~70 publications in SCI journals, including 4 PRL, 1 NanoLett., 21 PRB and 14 APL.
International advisory board member: Journal of Magnetism and Magnetic Materials, IEEE Magnetic Letters.