%0 journal article
%@ 1098-0121
%A Altynbaev, E.,Siegfried, S.-A.,Moskvin, E.,Menzel, D.,Dewhurst, C.,Heinemann, A.,Feoktystov, A.,Fomicheva, L.,Tsvyashchenko, A.,Grigoriev, S.

%D 2016
%J Physical Review  B
%N 17
%P 174403 
%R doi:10.1103/PhysRevB.94.174403
%T Hidden quantum phase transition in Mn1−xFexGe evidenced by small-angle neutron scattering
%U https://doi.org/10.1103/PhysRevB.94.174403
17 
%X The magnetic system of the Mn1−xFexGe solid solution is ordered in a spiral spin structure in the whole concentration range of x∈[0÷1]. The close inspection of the small-angle neutron-scattering data reveals the quantum phase transition from the long-range ordered to short-range ordered helical structure upon increase of Fe concentration at x∈[0.25÷0.4]. The short-range order (SRO) of the helical structure is identified as a Lorentzian contribution, while long-range order is associated with the Gaussian contribution into the scattering profile function. The scenario of the quantum phase transition with x as a driving parameter is similar to the thermal phase transition in pure MnGe. The quantum nature of the SRO is proved by the temperature-independent correlation length of the helical structure at low- and intermediate-temperature ranges with remarkable decrease above certain temperature TQ. We suggest the x-dependent modification of the effective Ruderman-Kittel-Kasuya-Yosida exchange interaction within the Heisenberg model of magnetism to explain the quantum critical regime in Mn1−xFexGe.