An atom's net magnetic dipole moment is the vector sum of its orbital and the spin magnetic moment. Some materials possess a finite magnetic moment due to the unpaired electrons in each atom and are called paramagnets. These moments are randomly oriented without a magnetic field; thus, the net moment is zero. Under an external field, the torque acting on a moment tends to align it along the field's direction. However, the atom's random thermal motion tries to disorient the moment. These two competing effects align only a few moments along the field direction, which generates an additional magnetic field proportional to the material's magnetization. This magnetization equals the total magnetic moment per unit volume. The resultant field is the sum of the external and induced fields. Curie's Law states that the magnetization is directly proportional to the applied magnetic field and inversely proportional to the temperature. Unlike diamagnets, paramagnets attract the magnetic field, and the relative permeability of paramagnets is slightly greater than unity. The susceptibility is positive and temperature-dependent for paramagnets.