Investigating the phase diagram of thin film MnSi

We have charted the magnetic phase diagram of thin film MnSi grown on a Si substrate via magnetization, magnetic susceptibility, first-order reversal, planar Hall, polarised neutron reflectometry and small-angle neutron scattering data, tracking carefully the field and temperature history. Our experimental results are supported by micromagnetic simulations, which jointly reveal a magnetic phase diagram dominated by a field-induced unwinding of an out-of-plane propagating helical wavevector. Below 2 K a discrete phase regime can be discerned unambiguously. These observations provide insights into the integral role of magnetic anisotropy and dimensionality on the low-temperature phase diagram of thin film MnSi.