  The interplay between structure, magnetism and superconductivity in single
crystal Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$ (x=0.047) has been studied using
high-resolution X-ray diffraction by monitoring charge Bragg reflections in
each twin domain separately. The emergence of the superconducting state is
correlated with the suppression of the orthorhombic distortion around
\emph{T}$_\texttt{C}$, exhibiting competition between orthorhombicity and
superconductivity. Above \emph{T}$_\texttt{S}$, the in-plane charge correlation
length increases with the decrease of temperature, possibly induced by nematic
fluctuations in the paramagnetic tetragonal phase. Upon cooling, anomalies in
the in-plane charge correlation lengths along $a$ ($\xi_{a}$) and $b$ axes
($\xi_{b}$) are observed at \emph{T}$_\texttt{S}$ and also at
\emph{T}$_\texttt{N}$ indicative of strong magnetoelastic coupling. The
in-plane charge correlation lengths are found to exhibit anisotropic behavior
along and perpendicular to the in-plane component of stripe-type AFM wave
vector (101)$_{\rm O}$ below around \emph{T}$_\texttt{N}$. The temperature
dependence of the out-of-plane charge correlation length shows a single anomaly
at \emph{T}$_\texttt{N}$, reflecting the connection between Fe-As distance and
Fe local moment. The origin of the anisotropic in-plane charge correlation
lengths $\xi_{a}$ and $\xi_{b}$ is discussed on the basis of the antiphase
magnetic domains and their dynamic fluctuations.
