  We present 75As nuclear magnetic resonance data from measurements of a series
of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ crystals with $0.00 \leq x \leq 0.075$ that
reveals the coexistence of frozen antiferromagnetic domains and
superconductivity for $0.060 \leq x \leq 0.071$. Although bulk probes reveal no
long range antiferromagnetic order beyond $x = 0.06$, we find that the local
spin dynamics reveal no qualitative change across this transition. The
characteristic domain sizes vary by more than an order of magnitude, reaching a
maximum variation at $x = 0.06$. This inhomogeneous glassy dynamics may be an
intrinsic response to the competition between superconductivity and
antiferromagnetism in this system.
