Neutron magnetic moment
The neutron magnetic moment is the magnetic moment of the neutron. It is of particular interest, as magnetic moments are created by the movement of electric charges. Since the neutron is a neutral particle, the magnetic moment is an indication of substructure. For a time, the neutron was thought to be made of a proton, with a charge of +1 e and an electron, with a charge of −1 e, whose charge would cancel out. However, since the advent of the quark model, it is now known that the neutron is made of one up quark (charge of +2/3 e) and two down quarks (charge of −1/3 e).
The magnetic moment is negative which means that the neutron's angular momentum has a tendency to align antiparallel to a magnetic field rather than parallel to the field. The non-zero magnetic moment of the neutron indicates that it is not an elementary particle, as it carries no net charge but still interacts with a magnetic field.