
\begin{tikzpicture}[scale=0.8]
    \begin{axis}[
        xlabel=$L^y$,
        xtick={0.1, 0.2, 0.3, 0.4},
        xticklabels={1, 2, 3, 4},
        width=4.5cm,
        height=4.5cm,
        y tick label style={
            /pgf/number format/.cd,
            fixed,
            fixed zerofill,
            precision=1,
            /tikz/.cd
        },
        ymin=8.1,
        ymax=9.1,
        x tick label style={rotate=0},
        legend style={font=\small},
        ylabel=\textbf{Recall@10},
        y label style={at={(0.75, 1.03)},rotate=270,anchor=south east},
        ytick distance = 0.3,
        grid=major,
        grid style=dashed,
        ]
        \addplot[mark=square*,blue]  
          coordinates{
            (0.1, 8.39) (0.2, 8.72) (0.3, 8.78) (0.4, 8.78)
        };
    \end{axis}
\end{tikzpicture}
\hspace{5mm}
\begin{tikzpicture}[scale=0.8]
    \begin{axis}[
        xlabel=$L^y$,
        xtick={0.1, 0.2, 0.3, 0.4},
        xticklabels={1, 2, 3, 4},
        width=4.5cm,
        height=4.5cm,
        y tick label style={
            /pgf/number format/.cd,
            fixed,
            fixed zerofill,
            precision=1,
            /tikz/.cd
        },
        ymin=5.2,
        ymax=5.8,
        x tick label style={rotate=0},
        legend style={font=\small},
        ylabel=\textbf{NDCG@10},
        y label style={at={(0.75, 1.03)},rotate=270,anchor=south east},
        ytick distance = 0.2,
        grid=major,
        grid style=dashed,
        ]
        \addplot[mark=triangle*,red]
          coordinates{
            (0.1, 5.41) (0.2, 5.58) (0.3, 5.63) (0.4, 5.62)
        };
    \end{axis}
\end{tikzpicture}