Earth's core is a giant liquid iron ball actually. If I know well, the magnetic field of our planet (that protects the surface from some particles comes from the Sun) can exist because as Earth rotates, the liquid iron core also rotates, and it generates a magnetic field.
However, ferromagnetism has strict conditions. How can the liquid and hot core still be ferromagnetic? How is it possible for Earth to have a magnetic field generated by a body that is not even solid?