Magnetic texture evolution within uniaxial kagome ferromagnets immediately below Curie temperature

Magnetic textures such like skyrmion and skrmionic bubbles attracts attention in connection with topology of electronic structures. Such texture formation usually occurred slightly below Curie temperature (T_c) due to competition of micromagnetic parameters that change rapidly with approaching T_c. We examined magnetic texture within two uniaxial kagome ferromagnets: Co₃Sn₂S₂ (T_c=176 K) studied extensively as a Weyl-semimetal and Fe₃Sn₂ (T_c= 657 K) interested for its massive Dirac fermions. In-situ Lorentz microscopy was performed during cooling across T_c under zero field. In Co₃Sn₂S₂, nucleation of bubble domains followed by their spontaneous reorganization occurred in narrow temperature range immediately below T_c,, whereas the domain wall motion was mostly frozen below 160 K. The morphology of the domains also depended on cooling rate through domain wall creep associated with thermal depinning. The magnetic phase diagram is influenced by slow spin dynamics also, hence is not determined uniquely as a function of field and temperature. In contrast such creep motion did not occur in Fe₃Sn₂ immediately below T_c, whereas domain wall motion occurred continuously in wide temperature range down toward room temperature.