hi,

yes you can.

with 60 percent or 6.5 cgpa in your masters degree and a valid GATE score is enough for admission in ph.d.

if you are an exceptional candidate of iit with 8.0 cgpa and a valid GATE score then you can also apply for ph.d.

(this sometimes vary for different universities, so if you want to know about any particular university then comment)

Hello,

The eligibility for phd is  Master's degree or dual degree or equivalent with a good academic record and a valid GATE  score.

If you've completed your masters along with GATE you are eligible for applying. Just with only gate score you can apply to masters not phd.

Hope it helps.