Spin-fluctuation heat capacity at magnetic phase transition in the Co,Fe doped MnSi

Abstract

An universal line revealing an independence of spin fuctuation contributions to the heat capacity on impurity content and its nature is discovered in the helical phase of Mn(Co,Fe)Si. This situation declares an invariance of the heat capacity of spin subsystem under doping, which probably arises as a result of relative stiffness of the helical spin structure in respect to the impurity spins. On the other hand the situation drastically changes at the helical fuctuation region when no long range spin order exists.