The YTick location and label are separate properites, though by default are the same value. I would probably try to do this by changing the YTickLabels on the right axis (but not the YTick location/values).
I'd modify your PlotDataButtonPushed callback to this.
function PlotDataButtonPushed(app, event)
yyaxis(app.UIAxes,"left");
xlabel(app.UIAxes,'Range')
ylabel(app.UIAxes,'dBsm')
title(app.UIAxes,'dBsm Vs Meter-Sqaure Graph')
plot(app.UIAxes,app.b,app.c)
ymin = min(app.c);
ymax = max(app.c);
ylim(app.UIAxes,[ymin ymax]);
yyaxis(app.UIAxes,"right");
ylabel(app.UIAxes,'Meter Square')
ylim(app.UIAxes,[ymin ymax]);
app.UIAxes.YAxis(2).TickLabels = 10.^(str2double(app.UIAxes.YAxis(1).TickLabels)/10);
end
