Ripple when switching on MOSFETs with PWM
First, your schematic (or circuit) probably Lacks a ground connection between your two power supplies. 

Second, driving a MOSFET for power application would be better with a push-pull topology.

Third, as Enric said, how long are your wires? with those type of circuits, it they must be as short as possible.

Can you provide pictures of your test setup? this would help us a lot.