pgfplots, get the axis exponent in scientific notation
Working on the solution proposed in Automatically put PGFPlots xtick scale label in x axis label, I came up with this totally automatic solution (even if a bit dirty):
\documentclass{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.14}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
xtick scale label code/.code={\pgfmathparse{int(-#1)}$x \cdot 10^{\pgfmathresult}$},
every x tick scale label/.style={at={(xticklabel cs:0.5)}, anchor = north},
ytick scale label code/.code={\pgfmathparse{int(-#1)}$y \cdot 10^{\pgfmathresult}$},
every y tick scale label/.style={at={(yticklabel cs:0.5)}, anchor = south, rotate = 90},
]
\addplot coordinates { (0.0001,0.001)(0.0002,0.002)(0.0003,0.003) };
\end{axis}
\end{tikzpicture}
\end{document}
which produce the following output:
and automatically adapts to the data order of magnitude.