Does zxms6004ff come with flyback diode internally?
It has over voltage clamping - up to 90mJ. You'll have to look at the power dissipation to see how frequently it can switch.  

The MOSFET itself turns on to absorb much of the inductive energy. 

If you add a diode across the inductance (not D-S) the MOSFET will not turn on from overvoltage, but the current will die off more slowly.