begin{axis}[
    %legend style={at={(1.05,0.05)}, %gibt Ort für Legende an
    %anchor=south west},
    %axis x line=bottom,    % erzeugt x-Achse mit Pfeil
    %axis y line=left,  %
    width=15.5cm,
    height=10cm,
    %scaled ticks=false,
    %ymin=0,
    xmin=-0.5,
    xmax=5,
    ymin=0,
    ymax=5,
    xtick={0,1,2,3,4},
    xticklabels={Fe2O3,1,2,3,4},
    bar width=50pt,
    %ytick={},
    %yticklabels={},
                %use un%%ts,
                %x unit=-,
                %x unit prefix=,
                %y unit=frac{m}{s},
                %y unit prefix=,
        xlabel=Subsequential Treatments over Time ,
    ylabel=Auger Peak to Peak Height Ratio Fe:O,
            x tick label style= {rotate=90,anchor=east},
            ybar stacked]



    addplot [draw=white, very thin]
            coordinates {(0,1) (1,1) (2,3) (3,2) (4,1.5)};
            addplot [draw= blue, fill=blue]
            coordinates {(0,1) (1,1) (2,3) (3,2) (4,1.5)};


            %node at (100,1) [orange!50!yellow]{small{ZnO-h}};


end{axis}
end{tikzpicture}

caption[Auger Spectrum of HOPG]{Auger Peak to Peak Height Ratios of Fe:O at an primary electron beam   of unit{2.0}{keV}.}
 label{Auger_ratio_histogram_}
        end{figure}`