MEISSNER EFFECT Meaning and
Definition
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The Meissner effect, also known as the Meissner-Ochsenfeld effect, is a fundamental principle of superconductivity wherein a material will expel any applied magnetic field from its interior when cooled below its critical temperature. Discovered in 1933 by Fritz Meissner and Robert Ochsenfeld, this phenomenon is observed in certain types of materials called superconductors.
When a superconductor is cooled below its critical temperature, which is specific to each material, it undergoes a phase transition, enabling it to conduct electric current with zero electrical resistance. Simultaneously, the Meissner effect causes the superconductor to exhibit perfect diamagnetism. This means that any external magnetic field attempting to penetrate the material will be quickly expelled. As a result, the superconductor repels the magnetic field and creates a perfect and persistent magnetic shield around it.
The Meissner effect occurs due to the formation of microscopic superconducting currents, known as supercurrents, within the material in response to the applied magnetic field. These supercurrents generate their own magnetic field, which opposes the external field and creates a repulsive force. Consequently, the magnetic field lines are pushed outside the superconducting material, thereby preventing any magnetic flux from passing through.
The Meissner effect has significant technological implications, particularly in fields such as magnetic levitation and high-speed transportation. By utilizing superconductors and the Meissner effect, objects can be suspended and propelled using magnetic fields, enabling efficient and frictionless transportation systems. Furthermore, this effect has been instrumental in the development of advanced magnetic resonance imaging (MRI) systems used in medical diagnostics.
Etymology of MEISSNER EFFECT
The term "Meissner effect" is named after the German physicist Walther Meissner. He first observed this phenomenon in 1933 along with Robert Ochsenfeld, which is why it is sometimes also referred to as the "Meissner-Ochsenfeld effect". The name Meissner effect is widely used to define the complete expulsion of magnetic field lines from a superconductor when it transitions into its superconducting state.
