International conference on Magnetism and Spintronics: “Sol-Skymag 2017”


Magnetic Skyrmions are one of the fascinating and promising objects because of their small size and stability to perturbations such as electric currents and magnetic fields [1-4]. The major mechanism to stabilize small Skyrmions in ferromagnet/heavy-metal bilayers is the presence of Dzyaloshinskii-Moriya interaction (DMI). In thin films, the DMI arises at the interface between ferromagnet and heavy metal due to the presence of spin-orbit interaction and broken inversion symmetry [4, 5]. In this work we investigate the stability and internal structure of an isolated Skyrmion in bilayer (ferromagnet/heavy metal) and trilayer (heavy metal 1/ferromagnet/heavy metal 2) nanodisks. We study the static properties of the Skyrmions and obtain the phase diagrams of the Skyrmion existence depending on the thickness of the ferromagnetic layer and the DMI strength. We demonstrate the importance of fully taking into account the dipolar interaction even for a few atomic layers thin nanodisk and that together with DMI it has the stabilizing effect and defines the Skyrmion configuration. For the trilayer structures with two heavymetal interfaces (corresponding to two interfacial DMIs), we show that the type and configuration of the Skyrmion can be controlled by the thickness of ferromagnet. Furthermore, the interplay of two interfacial DMIs can lead to the formation of magnetic structures with higher winding number.

[1] N. Nagaosa and Y. Tokura, Topological properties and dynamics of magnetic skyrmions, Nat. Nanotechnol. 8, 899-911 (2013),

[2] A. Hoffmann, S. Bader, Opportunities at the Frontiers of Spintronics, Phys. Rev. Appl. 4, 047001 (2015).

[3] A. Fert, V. Cros, J. Sampaio, Skyrmions on the track, Nat. Nanotechnol. 3, 152-156 (2013).

[4] J. Sampaio, V. Cros, S. Rohart, A. Thiaville, and A. Fert, Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures, Nat. Nanotechnol. 8, 839-844 (2013).

[5] S. Heinze, et al., Spontaneous atomic-scale magnetic skyrmion lattice in two dimensions, Nat. Phys. 7, 713–718 (2011).

K. Chihay1,2*, J. Barker3 , V. Rodionova1,2 , O. Tretiakov3,4

1 STP Fabrica Immanuel Kant Baltic Federal University, Kaliningrad, Russia

2 Center for Functionalized Magnetic Materials, Immanuel Kant Baltic Federal University, Kaliningrad, Russia

3 Institute for Materials Research, Tohoku University, Sendai, Japan

4 School of Natural Sciences, Far Eastern Federal University, Vladivostok, Russia

Correspondence to:  

Immanuel Kant Baltic Federal University,

Gaidara 6, Kaliningrad, 236022, Russia


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24th International Symposium on Metastable, Amorphous and Nanostructured Materials

     Ni-Fe-Ga Heusler-type alloys is a promising candidate for solid-state room temperature refrigeration due to its large reversible elastocaloric effect [1, 2]. One of the few disadvantages is their production process that consists of arc-melting of pure element followed by long-term annealing. In contrary, rapid-quenching method is found to be a fast way to produce a large amount of samples in a single step. Here, we report on martensitic phase transition in Cu-doped Ni-Fe-Ga ribbons, prepared by melt spinning method. Austenitic L21 cubic phase was found at room temperature along with amorphous hallo (Fig. 1a). Twinning effect with period of 180-300 nm was observed on the free surface (surface that had no contact with the wheel) within 40-60 micron crystallites (Fig. 1c). This is related to the residual martensitic phase in the film. Martensitic transition temperatures were obtained from resistivity curves and DSC measurements. Resistivity curves show traditional step-like behavior indicating martensitic phase transition (Fig. 1b). DSC curves demonstrate two overlapped peaks for both cooling and heating processes that can be related to premartensitic phenomena (Fig. 1d). Average martensitic transition temperature Tm was evaluated to be 264 K (from resistivity curves) and 273 K (from DSC). Low-field (0.01 T) thermomagnetic curves show small temperature hysteresis in the same area confirming the martensitic phase transition. Curie temperature value Tc = 269 K was evaluated by tangential method. It was also found that magnetic field has a negligible influence on martensitic transition temperatures (Fig. 1e).


Fig 1. a) XRD pattern made at RT; b) Thermomagnetic and resistivity curves; c) SEM images of the free surface; d) DSC heating/cooling curves; e) Resistivity curves measured in magnetic field of 1, 2 and 5 T

[1] Y. Xu, B. Lu, W. Sun, A. Yan and J. Liu, Applied Physics Letters 106, 201903 (2015).

[2] Y. Li, D. Zhao, J. Liu, Scientific Reports 6, 25500 (2016).

S. Shevyrtalov1 , R. Varga2 , T. Ryba2 , M. Gorshenkov3 , V. Rodionova1

1 Center for Functionalized Magnetic Materials, Immanuel Kant Baltic Federal University, 236041, Kaliningrad, Russian Federation

2 Institute of Physics, Faculty of Science, P.J. Safarik University, Park Angelinum 9, 041 54, Kosice, Slovakia

3 National University of Science and Technology MISiS, 4, Leninskii Pr., Moscow, 119049, Russia 

Correspondence to: 

Immanuel Kant Baltic Federal University,

Gaidara 6, Kaliningrad, 236022, Russia

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