"Tidal effects are not related to the magnetic field. The earth's core is mainly liquid iron and nickel, with a solid iron-nickel inner core. There will be convection and rotation, and therefore dynamo effects even without the moon."

It is outside my field. The report I read said that the moon's gravitational field is responsible for keep the Earth's core molten, at least the outer edge of it now that they say the core itself is actually a single iron crystal.