Magus Archetypes

[Jurai]

Is there an official Magus archetype for spontaneous casting, and what is it called?

[Chaosvii7]

Pretty sure Eldritch Scion is a spontaneous caster. It also turns the Magus into a CHA-based caster, if you're into that sort of thing.

[Psyren]

Yes, Eldritch Scion is first-party and spontaneous. Here's the link: http://www.d20pfsrd.com/classes/base-classes/magus/archetypes/paizo---magus-archetypes/eldritch-scion