On peut utiliser `error bars/y dir=both, error bars/y fixed=6` :
\documentclass{article}
\usepackage{pgfplots}
\begin{document}
\begingroup
\centering
\begin{tikzpicture}
\begin{axis}[
xlabel={SV duration (min)},
ylabel={correlation length $\kappa$ (nm)},
axis lines=left,
grid=major,
%xmin=0,
xmax=3000,
ymin=0,
ymax=700,
xmode=log,
log ticks with fixed point,
width=0.85\textwidth,grid=major,
error bars/y dir=both,
error bars/y fixed=6,
]
\addplot [blue,mark size=0.5pt,only marks] coordinates {(10,111)(10,87)(10,112)(50,116)(50,153)(100,131)(100,124)(100,172)(200,113)(200,102)(200,95)(300,74)(300,87)(300,116)(300,94)(400(102)(400,69)(400,127)(600,299)(600,201)(600,221)(700,214)(700,156)(700,263)(800,128)(800,96)(800,116)(900,185)(900,183)(900,158)(1000,160)(1000,150)(1000,162)(1000,154)(1100,181)(1100,132)(1100,127)(1200,127)(1200,154)(1200,122)};
\addplot [red,mark size=0.5pt,only marks] coordinates {(1,115)(10,119)(20,138)(30,100)(100,126)(140,139)(190,110)(300,150)(400,178)(1000,563)(2900,117)};
%\addplot [mark=*,mark size=1.5pt,red,thick,smooth] table {table_correlation_20200206.txt};
%\addplot [mark=*,mark size=1.5pt,blue,thick,smooth] table {table_correlation_20200213.txt};
\legend{20200213,20200206};
\end{axis}
\end{tikzpicture}
\endgroup
\end{document}
![alt text][1]
[1]: https://texnique.fr/osqa/upfiles/Screen_Shot_2020-02-20_at_17.44.59.png<img src="/upfiles/Screen_Shot_2020-02-20_at_17.44.59.png" style="width: 100%;"/>
