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We study a classical ferromagnetic Heisenberg model in the presence of Dzyaloshinskii-Moriya interactions on the corner-shared triangle lattice formed by the Mn sites of MnSi. We show that a sizable spin helicity can be obtained only when the microscopic Moriya vectors lie parallel to the Mn-Mn bonds. Further, such vectors are shown to produce an unpinned helical order characterized by a particular ordering wavevector magnitude but unpinned direction, dubbed partial order, at physically realizable temperatures. A consequence of such an unpinned helical ordering is that the neutron scattering intensity is sharply peaked at this wavevector magnitude. The surface formed by connecting these wavevectors is a sphere, around which the neutron scattering weight is spread. We further show that the observed neutron scattering intensity can be anisotropic along this surface and that this anisotropy is dependent on the experimentalists choice of lattice Bragg peak through a geometric factor. A neutron scattering measurement near the Bragg point ($frac{2pi}{a}$,$frac{2pi}{a}$,0) naturally leads to a highest intensity along the (1,1,0) direction consistent with the observed anisotropy in MnSi [Pfleiderer {it{et al.}} Nature {bf{427}} 227 (2004)]. A possible mechanism for pinning the helical order, and a way to distinguish an ordered and a partially ordered state in the context of neutron scattering are discussed.
We report comprehensive small angle neutron scattering (SANS) measurements complemented by ac susceptibility data of the helical order, conical phase and skyrmion lattice phase (SLP) in MnSi under uniaxial pressures. For all crystallographic orientat
We report the observation of a highly unusual Hall current in the MnSi in an applied pressure P = 6-12 kbar. The Hall conductivity displays a distinctive step-wise field profile quite unlike any other Hall response observed in solids. We identify the
The archetype cubic chiral magnet MnSi is home to some of the most fascinating states in condensed matter such as skyrmions and a non-Fermi liquid behavior in conjunction with a topological Hall effect under hydrostatic pressure. Using small angle ne
Magnetic frustration in Fe$_3$PO$_4$O$_3$ has been shown to produce to an unusual magnetic state below T$_N = 163$ K, where incommensurate antiferromagnetic order is restricted to nanosized needle-like domains, as inferred from neutron powder diffrac
Chiral nematic liquid crystals sometimes form blue phases characterized by spirals twisting in different directions. By combining model calculations with neutron-scattering experiments, we show that the magnetic analogue of blue phases does form in t