Skyrmions and spirals in cubic chiral magnets

Magnetic skyrmions are two-dimensional topologicallyprotected spin textureswith particle like properties which may crystallize inlattices that are typically oriented perpendicular to the magnetic field. Theirfirst observation was in the archetype cubic helimagnet MnSi, where skyrmionlattices appear spontaneously in the A-phase located just below the transitiontemperature and under magnetic fields. Single crystal cubic helimagnets host, besideskyrmion lattices, a variety of helimagnetic phases that are stabilized bythree hierarchically ordered interactions, being the strongest ferromagnetic,the weaker Dzyaloshinsky-Moriya which is non-zero due to the absence ofinversion symmetry, and the weakest anisotropy interaction. The competitionbetween these and the Zeeman interaction results in a relatively generic phasediagram for cubic helimagnets. Albeit this relative generic phase diagram, eachof these systems have their own particularities. This thesis mainly presentsresults of magnetization, ac susceptibility and neutron scattering studies offour cubic helimagnets: MnSi, Mn_1-xFe_xSi, Fe_1-xCo_xSi and Cu₂OSeO₃