The earth's magnetic field is created from molten iron in the core of the earth. To create an "artificial" magnetic field that acted as the earth's magnetic field does, one would have to put some magnetic material in the core of the planet or moon and ensure that it rotated. read more
Because of its magnetic properties, holmium has been used to create the strongest artificially-generated magnetic fields when placed within high-strength magnets as a magnetic pole piece (also called a magnetic flux concentrator). Since it can absorb nuclear fission-bred neutrons, the element is also used in nuclear control rods. read more