Clear anomalies establish the Skyrmion lattice unambiguously as a thermodynamic phase. The evolution of the specific heat anomalies, the field dependence of the entropy released at the phase transitions, and the temperature versus field dependence of crossover lines provide striking evidence of a tricritical point at 340 mT and 28.5 K. The existence of this tricritical point represents strong support of a helimagnetic Brazovskii transition, i.e., a fluctuation-induced first-order transition at H = 0.
Original Publication:
A. Bauer, M. Garst and C. Pfleiderer (2013). Specific Heat of the Skyrmion Lattice Phase and Field-Induced Tricritical Point in MnSi Phys. Rev. Lett. 110 177207