2007/04/05 by S. V. Grigoriev, S. V. Maleyev S. V. Grigoriev, Grigoriev, S. V. Maleyev S. V.
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Magnetic properties of thin films #Rare-earth and actinide compounds #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.0704.0683
5 pages, 3 figures
arxiv created 2007/04/05 · openalex publication_date 2007/04/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The polarized neutron scattering in helimagnetic MnSi at low T reveals existence of a partially disordered chiral state at ambient pressure in the magnetic field applied along <111> axis below the first order transition to the non-chiral ferromagnetic state. This unexpected phenomenon is explained by the analysis of the spin-wave spectrum. We demonstrate that the square of the spin-wave gap becomes negative under magnetic field applied along <111> and <110> but not along the <100> direction. It is a result of competition between the spin-wave interaction and cubic anisotropy. This negative sign means an instability of the spin wave spectrum for the helix and leads to a destruction of the helical order, giving rise to the partially disordered state below the first order ferromagnetic transition.