Microscopic evidence of skyrmion lattice using neutrons

Using small angle neutron scattering at the instrument MIRA at the FRM II and V4 at the Helmholtz Centre Berlin, Tim Adams of the TU München physics department has delivered the missing microscopic evidence for the topological characteristics of a long reaching skyrmion lattice.

Operating principle and typical data of Renninger scans at V4. (a) Ewald-sphere depiction of Renninger scans. (b) Typical scattering pattern obtained by a sum over a rocking scan around Phi after background subtraction recorded at high T. (c) Intensity as a function of rocking angle Phi in a Renninger scan. The intensity was integrated over the areas of boxes 1 and 2 in (b).

The discovery of the skyrmion lattices has evoqued a large interest since 2009. An open question was the direct microscopic evidence of the special topological properties of a skyrmion lattice in samples. 

Using small angle scattering at MIRA at FRM II and V4 at HZB, Tim Adams and the same team from Munich and Cologne have succeeded in finding the evidence. They report in Physical Review Letters about their discovery. Using a neutron scattering trick, the so-called Renninger scan, they managed to highly suppress parasitic scattering signals. 

Original Publication:  

Long-Range Crystalline Nature of the Skyrmion Lattice in MnSi Phys. Rev. Lett. 107, 217206 (2011) 

T. Adams, S. Mühlbauer, C. Pfleiderer, F. Jonietz, A. Bauer, A. Neubauer, R. Georgii, P. Böni, U. Keiderling, K. Everschor, M. Garst, and A. Rosch 

DOI: 

10.1103/PhysRevLett.107.217206