Depending upon their behavior in an external magnetic field, superconductors are divided into two types:

a) Type I superconductors and b) Type II superconductors

Let us discuss them one by one:

1) Type I superconductors:

a). Type I superconductors are those superconductors which loose their superconductivity very easily or abruptly when placed in the external magnetic field. As you can see from the graph of intensity of magnetization (M) versus applied magnetic field (H), when the Type I superconductor is placed in the magnetic field, it suddenly or easily looses its superconductivity at critical magnetic field (Hc) (point A).

After Hc, the Type I superconductor will become conductor.

b). Type I superconductors are also known as soft superconductors because of this reason that is they loose their superconductivity easily.

c) Type I superconductors perfectly obey Meissner effect.

d) Example of Type I superconductors: Aluminum (Hc = 0.0105 Tesla), Zinc (Hc = 0.0054)

2) Type II superconductors:

a). Type II superconductors are those superconductors which loose their superconductivity gradually but not easily or abruptly when placed in the external magnetic field. As you can see from the graph of intensity of magnetization (M) versus applied magnetic field (H), when the Type II superconductor is placed in the magnetic field, it gradually looses its superconductivity. Type II superconductors start to loose their superconductivity at lower critical magnetic field (Hc1) and completely loose their superconductivity at upper critical magnetic field (Hc2).

b) The state between the lower critical magnetic field (Hc1) and upper critical magnetic field (Hc2) is known as vortex state or intermediate state.

After Hc2, the Type II superconductor will become conductor.

c). Type II superconductors are also known as hard superconductors because of this reason that is they loose their superconductivity gradually but not easily.

c) Type II superconductors obey Meissner effect but not completely.

d) Example of Type II superconductors: NbN (Hc = 8 x 106 Tesla), Babi3 (Hc = 59 x 103 Tesla)

e) Application of Type II superconductors: Type II superconductors are used for strong field superconducting magnets.

Note: If you want the e books of superconductors or other topics at only Rupees 10 or Half a US Dollar then please check our “Winnerscience Books” page on top of our website.