Hidden quantum phase transition in Mn1-xFexGe evidenced by small-angle neutron scattering

E. Altynbaev, S.-A. Siegfried, E. Moskvin, D. Menzel, C. Dewhurst, A. Heinemann, A. Feoktystov, L. Fomicheva, A. Tsvyashchenko, S. Grigoriev

Research output

10 Citations (Scopus)

Abstract

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
Original languageUndefined
Pages (from-to)174403
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume94
Issue number17
DOIs
Publication statusPublished - 2016

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