Multiple magnetic states within the A-phase determined by field-orientation dependence of Mn0.9Fe0.1Si

We report three distinct regions within the A-phase in Fe-doped MnSi, based on the evolution of magnetoresistance and the Hall effect as a function of orientation of applied field. Fe impurities as pinning centers and crystalline anisotropy are found non-negligible only at the boundary of the A-phase. Electrical transport characteristics unique to the A-phase not only remain robust, but also indicate a freely rotating skyrmion lattice, decoupled from underlying crystal structure or impurity pinning.