Unusual Hall effect anomaly in MnSi under pressure

Phys Rev Lett. 2009 May 8;102(18):186601. doi: 10.1103/PhysRevLett.102.186601. Epub 2009 May 4.

Abstract

We report the observation of a highly unusual Hall current in the helical magnet MnSi in an applied pressure P=6-12 kbars. The Hall conductivity displays a distinctive stepwise field profile quite unlike any other Hall response observed in solids. We identify the origin of this Hall current with the effective real-space magnetic field due to chiral spin textures, which may be a precursor of the partial-order state at P>14.6 kbar. We discuss evidence favoring the chiral spin mechanism for the origin of the observed Hall anomaly.