If you just have one line to be plotted and you want one axes to be linear and the other to be log, then you can use semilogx() or semilogy() to do the plotting.
Those functions are plot() calls followed by setting the axes 'XScale' or 'YScale' properties to 'log' instead of the default linear.
If you want to have one line that is linear scale and another line that is log scale in the same plot, then you will need to use multiple axes in the same plot. The newer way to do that is yyaxis left and yyaxis right and use plot() or semilogx() or semilogy() as appropriate. The older way to do it is to use plotyy() -- you can specify one of the lines as plot() and the other as semilog*() as appropriate.
