The Meissner Effect, discovered in 1933 by German physicists Walther Meissner and Robert Ochsenfeld, is a key characteristic of superconductivity. It demonstrates that certain materials, when cooled below their superconducting critical temperature, can completely expel magnetic fields from within them.
In the superconducting state, materials abruptly lose all electrical resistance, allowing electric currents to flow without any energy loss. However, the discovery of the Meissner Effect revealed another peculiar property of superconductors: their ability to repel magnetic fields, known in physics as “perfect diamagnetism.”
In simpler terms, if a magnet is placed above a superconductor, it will levitate, as the magnetic field is being “pushed” out by the superconductor. This phenomenon, observable under laboratory conditions, provides vital insights into the magnetic properties of superconductors.
The Meissner Effect also has significant technological applications, especially in fields that require strong and precise magnetic field control. For instance, maglev trains use this principle for nearly frictionless travel, while in the medical field, MRI (Magnetic Resonance Imaging) machines utilize superconductors to generate strong and stable magnetic fields for detailed internal imaging of the human body.
In summary, the Meissner Effect is not only an important addition to superconducting theory but also a key foundation for the advancement of superconductor-based technologies.