Description:

I will present the observation of Skyrmion-like magnetic textures in the 2D itinerant ferromagnets FenGeTe2 (n = 3,4) by low-temperature magnetic force microscopy (MFM). In the absence of externally applied magnetic field, the MFM experiments at 1.6 K detected filamentary magnetic domain walls on such ferromagnets.  In order to gain a microscopic understanding of such domain structures, we developed a theoretical model combining itinerant magnetism and spin-orbit coupling on a triangular lattice. The ground state of the model consists of strikingly similar filamentary domain walls. When the ferromagnets were cooled down under the magnetic field of the MFM cantilever, the filaments were found to break into magnetic bubbles. The size of the bubbles could be varied by field-cooling the ferromagnets under external magnetic fields of varying strength. We identified uniaxial magnetic anisotropy as an important parameter in the model that interpolates between magnetic Skyrmions and ferromagnetic bubbles and explains the field-dependent MFM results. The work also uncovers new topological magnetic textures that merge properties of Skyrmions and ferromagnetic bubbles.

Goutam Sheet, Professor, Indian Institute of Science Education and Research, Mohali, India

Host: Venkat Chandrasekhar