Manganese monosilicide

Manganese monosilicide is a non-stoichiometric compound, meaning that the 1:1 Mn:Si composition, lattice constant and many other properties vary depending on the synthesis and processing history of the crystal.

[3] Electron spins in MnSi show dissimilar, yet regular spatial arrangements at different values of applied magnetic field.

Those arrangements are named helical, skyrmion, conical, and regular ferromagnetic.

They can be controlled not only by temperature and magnetic field, but also by electric current, and the current density required for manipulating skyrmions (~106 A/m2) is approximately one million times smaller than that needed for moving magnetic domains in traditional ferromagnets.

As a result, skyrmions in MnSi have potential application in ultrahigh-density magnetic storage devices.

Magnetic phase diagram of MnSi. At low temperatures, with increasing magnetic field, spins in MnSi form helical, conical, skyrmion (SkS) and regular ferromagnetic spatial structures. At high temperatures the spin orientation is random (paramagnetic)
Simulated and measured (by STXM ) images of helical, skyrmion and conical phases in FeGe . All magnetic properties are very similar in FeGe and MnSi, except for T c values.