  The ground state of the parent compounds of many high temperature
superconductors is an antiferromagnetically (AFM) ordered phase, where
superconductivity emerges when the AFM phase transition is suppressed by doping
or application of pressure. This behaviour implies a close relation between the
two orders. Understanding the interplay between them promises a better
understanding of how the superconducting condensate forms from the AFM ordered
background. Here we explore this relation in real space at the atomic scale
using low temperature spin-polarized scanning tunneling microscopy (SP-STM) and
spectroscopy. We investigate the transition from antiferromagnetically ordered
$\mathrm{Fe}_{1+y}\mathrm{Te}$ via the spin glass phase in
$\mathrm{Fe}_{1+y}\mathrm{Se}_{0.1}\mathrm{Te}_{0.9}$ to superconducting
$\mathrm{Fe}_{1+y}\mathrm{Se}_{0.15}\mathrm{Te}_{0.85}$. In
$\mathrm{Fe}_{1+y}\mathrm{Se}_{0.1}\mathrm{Te}_{0.9}$ we observe an
atomic-scale coexistence of superconductivity and short-ranged bicollinear
antiferromagnetic order.
