Abstract
Magnetic skyrmions are topological spin-textures having immense potential for energy efficient spintronic devices. Here, we report the observation of stable skyrmions in unpatterned Ta/Co2FeAl(CFA)/MgO thin film heterostructures at room temperature in remnant state employing magnetic force microscopy. It is shown that these skyrmions consisting of ultrathin ferromagnetic CFA Heusler alloy result from strong interfacial Dzyaloshinskii-Moriya interaction (i-DMI) as evidenced by Brillouin light scattering measurements, in agreement with the results of micromagnetic simulations. We also emphasize on room temperature observation of multiple skyrmions which can be stabilized for suitable combinations of CFA layer thickness, perpendicular magnetic anisotropy, and i-DMI. These results provide a significant step towards designing of room temperature spintronic devices based on skyrmions in full Heusler alloy based thin films.
Highlights
A novel magnetic pattern in which the magnetic moments exhibit a characteristic swirling configuration is referred to as a skyrmion[1,2,3]
Emt oaml.2e3ntthsa→St ithane dD→SMj .IIcnaitniablley,inthdeuDceMd Iinwaashceoanvsyidmereetadl to be of bulk origin, it was first proposed by Fert doped system or later by Bogdanov et al.[24] in multilayer structures by breaking the inversion symmetry at the interfaces between FM and nearby non-magnetic ultrathin layers
The studies clearly suggest that the topological nature of the skyrmions makes them very exciting for applications in spintronic devices, primarily due to the giant reduction in the threshold current density by five to six orders of magnitude compared to the current density reported in currently employed FMs for driving the domain walls[31,32]
Summary
Sajid Husain[1], Naveen Sisodia[1], Avinash Kumar Chaurasiya[2], Ankit Kumar[3], Jitendra Pal Singh 5, Brajesh S.Yadav[4], Serkan Akansel[3], Keun Hwa Chae 5, Anjan Barman[2], P. We report the observation of stable skyrmions in unpatterned Ta/Co2FeAl(CFA)/ MgO thin film heterostructures at room temperature in remnant state employing magnetic force microscopy. Various groups have focused on the ultrathin magnetic film/non-magnetic heavy metal interface[36,37] to explore the formation of skyrmions In these studies, there exists a plenty of room for varying the various control parameters, viz., material, thickness and the structure of the interfacial layer employed for the control of i-DMI, exchange and anisotropy constants, etc. The direct imaging of stable skyrmions at room temperature employing magnetic force microscopy (MFM) in trilayer stacks containing CFA full Heusler alloy ultrathin films is presented. The simulations clearly demonstrate that the realization of skyrmionic state is conceivable as a result of the competition between the i-DMI, anisotropy, exchange interaction and dipolar interaction in Ta/CFA/MgO heterostructure
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