Houssam Sabri started his Ph.D. in November 2019 at CentraleSupélec on modeling multiferroic skyrmion host and chiralmagnet CuO₂SeO₃. Based on density functional theory, Andan Effective Hamiltonian approach solved with Monte Carlo simulations,different phases of CuO₂SeO₃ (Helical state and skyrmionlattice phase...) are explored, as well as various other topological defects,which include 3D point defects such as Hedgehogs and Antihedgehogs and 3Dsolitons like Hopfion like defect are studied, to understand the stability, thephase transition mechanism, and interaction between theses topological defects.