antiferromagnetic (o-AF) and the tetragonal antiferromagnetic (t-AF) states of a weakly
underdoped Ba 1− x K x Fe 2 As 2 single crystal. We observed some characteristic changes
of the magnitude and the orientation of the magnetic field at the muon site which, due to the
fairly high point symmetry of the latter, allow us to identify the magnetic structure of the t-AF
state. It is the so-called, inhomogeneous double-Q magnetic structure with c-axis–oriented …