How do I plot a secondary y-axis in log scale?

I am unsure how to plot my secondary y-axis in log scale? I only want the secondary y-axis in the log scale not my primary y-axis or x-axis.

Answer 1

[dpb]

>> help plotyy
plotyy Graphs with y tick labels on the left and right
  plotyy(X1,Y1,X2,Y2) plots Y1 versus X1 with y-axis labeling
  on the left and plots Y2 versus X2 with y-axis labeling on
  the right.
  ...
  plotyy(X1,Y1,X2,Y2,FUN1,FUN2) uses FUN1(X1,Y1) to plot the data for
  the left axes and FUN2(X2,Y2) to plot the data for the right axes.
  ...

Ergo,

hA=plotyy(X1,Y1,X2,Y2,@plot,@semilogy)