Meissner Effect

Meissner Effect is the effect that converts a material from a normal state to a superconducting
state. When a material is called below a specified temperature at which the magnetic field
from the interior of the material is exploded, then this material is transformed into the
superconductor. This phenomenon is called the Meissner Effect.
The temperature required to convert the material into the superconductor is called the
transition temperature. This transition temperature is near absolute temperature (0 kelvin).
This superconductor material has zero electric resistance. The main importance of the
Meissner Effect is magnetic levitation, which is a process by which a body is suspended with
no support except a magnetic field.
Superconducting State
The superconducting state is the state where the material has zero electric resistance. At this
stage, the material loses all the resistance of the flow of electric current. When the material is
cooled below the transition temperature, it converts into the superconductor and reaches the
superconducting state. Mercury reaches the superconducting state when cooled down below
4.1 kelvin.
What is the Meissner Effect?

Walther Meissner and Robert Ochsenfeld, two German physicists, obtained the physical
process of the Meissner effect in the year 1933. Meissner Effect is the expulsion of the
magnetic field, which converts a material from a normal state to a superconducting state
when cooled down below the transition temperature.
When a magnetic field is applied at the higher value of temperature to the transition
temperature, the superconductor has a minor effect. These magnetic fields passed through the
superconductor quickly. At the lower value of temperature to the transition temperature, the
magnetic field is thrown out from inside the superconductor and bends on all sides of it when
the magnetic field is applied.
This explosion of the magnetic field is the generation of magnetisation inside the
superconductor due to no resistance flow of surface currents. This generated magnetization
inverse and opposite to the applied magnetic field, which neuters the magnetic field around
the superconductor.
Meissner State
he state at which the material becomes a superconductor is called the Meissner state. When
the magnetic field increases further to the specified value, and the material behaves like the
ordinary conductor, the Meissner state is broken down. This specified magnetic field value is
known as the critical magnetic field.
The more the value of temperature below the transition temperature decreases, the more the
value of the critical magnetic field is increased. The Meissner state can only be broken down
when the magnitude of the electric field is too strong. On the basis of this breakdown, there
can be two types of superconductors that may form.
 Type-I Superconductor: This superconductor excludes the magnetic field until the
superconductivity is destructed abruptly. Later, the magnetic field penetrates
completely—the critical value of the type-I superconductor too low.
 Type-II Superconductor: The type two superconductors keeps out the entire magnetic
field until a lower critical value is reached. The magnetic flux quantum, which
penetrates the superconductor, is now appearing. In this zone, the metal is no longer
remain a superconductor. If the value of the field increases to a higher critical value,
then the metal stops being a superconductor. This type of superconductor is made
with material that has high electric resistivity.
Diamagnetism property for Superconductor

The Meissner Effect says that the ideal diamagnetism is the important property of the
superconducting state. This statement can be proved with the relation of magnetic field and
magnetic field intensity.
The Meissner Effect suggests that the value of the magnetic field inside a superconductor is
zero.
B=0
The magnetic induction inside the specimen for the normal conditions is given by the
following equation.
B=o (H+I)
Here, I is the magnetization which is generated inside the specimen and H is the magnetic
field applied externally.
By both equation, we have,
0=o (H+I)
H=-I
H /I =-1=X
The diamagnetic material susceptibility is equal to -1, so the material is ideally diamagnetic.
Diamagnetism of superconductor
The superconductor has the magnetic susceptibility of -1 which makes it perfect
diamagnetism. This diamagnetic keeps magnetization which resists any applied magnetic
field, thus the superconductor feels repulsion by any magnetic field.
This repulsion force is the main reason for the levitation of a superconductor, under the
application of a magnet. If this magnetic field is separate or the temperature of the
superconductor rises above the transition temperature, the magnetization and surface currents
disappear, and the levitation will stop.
Contradiction of Meissner Effect
The Maxwell’s equation for electrodynamics is given by,
E=-dB/dt
The electric field is equal to zero for a superconductor.
0=-dB/dt
0=dB/dt
B=constant
According to Meissner, the magnetic field inside a superconductor is zero, but in this case the
magnetic field has constant value and is not equal to zero.
Meissner Effect Importance

The Meissner effect has importance in the field of superconductivity of the superconductor.
The magnetic levitation, which is the main concept of a bullet train and hyperloop, is also
discovered with the help of the Meissner effect. The importance of the Meissner Effect is
listed below.
 The Meissner Effect helps to understand the theory of superconductivity.
 The Meissner Effect is used in magnetic levitation, which means a body is suspended
with no support except a magnetic field.
 In coils of superconducting magnets, the Meissner Effect is applicable.
 The Meissner Effect says that the ideal diamagnetism is the crucial property of the
superconducting state.
 The Meissner Effect keeps the importance in high speed or fifth means of
transmission such as bullet trains and hyperloops.
Conclusion
Meissner Effect talks about the expulsion of the magnetic field, which helps convert material
from normal state to superconducting state, which is when cooled below the critical
temperature or transition temperature. The major importance of the Meissner Effect is in the
field of superconductivity and magnetic levitation.

Meissner Effect

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Meissner Effect

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Meissner Effect is the effect that converts a material from a normal state to a superconducting

What is the Meissner Effect?

Diamagnetism property for Superconductor

Meissner Effect Importance

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