Scaling investigation of the magnetic entropy change in helimagnet MnSi

摘要: The B20 compound MnSi exhibits a skyrmion phase in a certain range of temperature (T) and external magnetic ¯eld (H) in addition to the helimagnetic ordering. In this work, the magnetic entropy change (¢SM) in the single crystal helimagnet MnSi has been investigated by the scaling analysis. The ¢SM(T;H) curves in higher ¯eld range (2 kOe < H < 5.6 kOe) collapse onto an universal curve after scaling, which is independent of T and H. Based on this universal curve, the ¢SM(T;H) (excluding the skyrmion entropy change) at any T and H can be calculated. On the other hand, a small valley is found on the ¢SM(T) curve at » 28.5 K in the ¯eld range from » 1 kOe to » 2 kOe, which is resulted from the skyrmion phase. Subsequently, the magnetic entropy change of the skyrmion phase [¢SskX M (T;H)] can be derived by subtraction of the calculated ¢Scal M (T;H) from the experimental ¢Sexp M (T;H). The obtained results show that ¢SskX M reaches the maximum at » 1.6 kOe, which indicates the highest number of skyrmion vortices at that ¯eld.