paramagneettisuudessa

Paramagnetism is a form of magnetism that occurs only in the presence of an external magnetic field. Materials exhibiting paramagnetism are weakly attracted to this external field and tend to align their magnetic moments with the field. This alignment results in a net magnetization in the same direction as the applied field. When the external field is removed, the material loses its magnetization because the thermal motion of atoms disrupts the alignment of their magnetic moments.

Unlike ferromagnetic materials, which can retain their magnetization even after the external field is removed, paramagnetic materials do not exhibit spontaneous magnetization. The magnetic properties of paramagnetic substances arise from the presence of unpaired electrons in their atoms or molecules. These unpaired electrons possess intrinsic magnetic dipole moments, which can be thought of as tiny magnets. In the absence of an external field, these atomic magnetic moments are randomly oriented due to thermal agitation.

When an external magnetic field is applied, these atomic magnetic moments experience a torque that attempts to align them with the field. While not all moments align perfectly, a net alignment occurs, leading to the macroscopic magnetization observed in paramagnetic materials. The degree of magnetization is proportional to the strength of the applied magnetic field and inversely proportional to the temperature. This relationship is described by the Curie law for many paramagnetic substances. Common examples of paramagnetic materials include aluminum, platinum, and oxygen.