Latex pgfplots graph axis scaling [duplicate]

Question

I have the graph to the left. I want the graph to the right, or else I can't see the difference between the two lower ones.

\documentclass[a4paper,11pt]{article}
\usepackage{float}
\usepackage{tikz} \usetikzlibrary{trees}
\usetikzlibrary{pgfplots.groupplots}
\usepackage{siunitx}
\sisetup{per=slash, load=abbr}

\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{width=7cm, height=10cm, compat=1.4, every axis/.append style={thick}}
\begin{document}
\begin{figure}[H]
  \centering
  \pgfplotsset{
    scaled y ticks=false,
    scale only axis,
    legend style={at={(0,0.8)}, anchor=west, font=\tiny},
    xmin=7,
  }
  \begin{tikzpicture} [scale=0.7, font=\Large]
    \begin{axis}[
        title=Size of search tree linear scale,
        ylabel=Nodes,
        xtick=data,
        ymin=0, 
    xlabel=xlabel ]
  \addplot[smooth,mark=square*, mark options={solid},red, dashed]
  coordinates{ (7,29788) (8,16760) (9,8770) (10,14248) (11,11456) (12,14602) (13,17456) (14,13112)
  }; \label{ie_plot} \addlegendentry{IntPairExact}
  \addplot[smooth,mark=square*, mark options={solid},blue, dotted]
  coordinates{ (7,30142) (8,16836) (9,8960) (10,14390) (11,11584) (12,14694) (13,17634) (14,13242)
  }; \label{ia_plot} \addlegendentry{IntPairApprox}
  \addplot[smooth,mark=*,mark options={solid},black]
  coordinates{ (7,256300) (8,254888) (9,144484) (10,194390) (11,135874) (12,233684) (13,243624) (14,221408)
  }; \label{int_plot} \addlegendentry{Integer}
    \end{axis}
  \end{tikzpicture}

\end{figure}
\end{document}