Experimental study of the magnetic phase transition in the MnSi itinerant helimagnet

TitleExperimental study of the magnetic phase transition in the MnSi itinerant helimagnet
Publication TypeJournal Article
Year of Publication2008
AuthorsStishov SM, Petrova AE, Khasanov S, Panova GK, Shikov AA, Lashley JC, Wu D, Lograsso TA
Journal TitleJournal of Experimental and Theoretical Physics
Date PublishedMay
Type of ArticleArticle
ISBN Number1063-7761
Accession NumberISI:000257115900006
Keywordsbehavior, electron, LATTICE, manganese, MONOSILICIDES, pressure, RESISTIVE ANOMALIES, weak ferromagnetism

Magnetic susceptibility, heat capacity, thermal expansion, and resistivity of a high-quality single crystal of MnSi were carefully studied at ambient pressure. The calculated change in magnetic entropy in the temperature range 0-30 K is less than 0.1R, a low value that emphasizes the itinerant nature of magnetism in MnSi. A linear temperature term dominates the behavior of the thermal expansion coefficient in the range 30-150 K, which correlates to a large enhancement of the linear electronic term in the heat capacity. A surprising similarity between variation of the heat capacity, the thermal expansion coefficient, and the temperature derivative of resistivity through the phase transition in MnSi is observed. Specific forms of the heat capacity, thermal expansion coefficient, and temperature derivative of resistivity at the phase transition to a helical magnetic state near 29 K are interpreted as a combination of sharp first-order features and broad peaks or shallow valleys of yet unknown origin. The appearance of these broad satellites probably hints at a frustrated magnetic state in MnSi slightly above the transition temperature. Present experimental findings bring the current views on the phase diagram of MnSi into question.

Alternate JournalJ. Exp. Theor. Phys.