Diamagnetism

Diamagnetism is a fundamental property of all materials that causes them to be repelled by a magnetic field. This effect arises from the interaction between an external magnetic field and the orbital motion of electrons within an atom. Specifically, when a material is placed in a magnetic field, the electrons begin to precess, generating a tiny, opposing magnetic field that opposes the external field. This induced magnetic field, while weak, is the cause of diamagnetic repulsion. Unlike paramagnetism and ferromagnetism, diamagnetism is present in all substances, though it's often masked by stronger magnetic effects in materials with unpaired electrons. The strength of diamagnetism is inversely proportional to temperature, and its manifestation is most evident in materials with no permanent magnetic dipole moments. It is a quantum mechanical phenomenon, reflecting the response of electrons to the presence of an external magnetic field, resulting in a negative magnetic susceptibility.

Diamagnetism meaning with examples

• Certain organic compounds, due to their electron-paired structure, display diamagnetic properties. In a strong magnetic field, a sample of water, which is diamagnetic, can exhibit a slight repulsion, though this is often difficult to observe without specialized equipment. This repulsion effect, inherent in diamagnetic materials, is a fundamental response to magnetic fields.
• Scientists utilize the diamagnetic properties of some materials in magnetic levitation experiments. The weak repulsive force can, under specific conditions, counteract gravity to levitate an object. By precisely controlling the magnetic field, researchers have used diamagnetism to create a stable levitation.
• Measurements of the diamagnetic susceptibility of a material provide valuable insights into its electronic structure. Analysis of the diamagnetic response can help in understanding the interactions of electrons within the substance and determining its fundamental magnetic properties. This property can thus be used to gain information about material composition.
• Superconducting materials exhibit perfect diamagnetism, known as the Meissner effect. When cooled below their critical temperature and placed in a magnetic field, they completely expel the field, which makes it very unique. This leads to complete magnetic levitation above the material, which is useful in certain types of advanced technology.
• In analytical chemistry, diamagnetic substances are used as the basis for nuclear magnetic resonance (NMR) spectroscopy. The external magnetic field interacts with the magnetic moments of atomic nuclei, providing valuable information about the structure and composition of molecules by using magnetic fields.