Determination of crystallographic chirality of MnSi thin film grown on Si (111) substrate

MnSi is a prototypical chiral cubic magnet, in which swirling magnetic objects referred to as magnetic skyrmions appear. It is expected that the thin film of MnSi may expand the range of the magnetic skyrmion lattice phase in the temperature--magnetic field diagram. On the other hand, the MnSi film on an achiral Si (111) substrate may suffer from chiral twin formation. We succeeded in visualizing the domain structure of the chirality and axis orientation of a MnSi thin film by using a combination of transmission electron microscopy and x-ray reflectivity measurement. Only two types of domains were found on a Si (111) substrate. The information is essential for the challenge of homochiral film fabrication.