Myrrh, Frankincense, and Steel: Kurald Galain's Guide to the Magus

[Kurald Galain]

is there any way to use magus as dedicated tank in caster only party

The obvious question is, what level are you playing at.

The best defensive archetype is Staff Magus. A decent alternative is Skirnir but only at level 8 and up (it's pretty much a trap below that). Spire Defender, despite the name, doesn't actually improve your defenses any, and neither does Armored Battlemage (and that's precisely why it's not a very good trade; note that light armor + dexterity gives you a better AC than heavy armor does).

But you can also pick any archetype you like, and use your spells for defense. Open every combat with casting Shield, Mirror Image, or Displacement. If your Magus is based on dexterity, this will make you a suitable tank.

(edit) Aanother good archetype is Eldritch Scion with the Arcane bloodline. From level four, it gives you a free defensive spell every combat at no action cost; at level eight, it adds Displacement on top of that.