Question

A Type II superconductor is characterized by value of London penetration depth to coherence length being :­

1) 0

2) 1

3) less than 1

4) more than 1

Answer 1

Gives

Coherent length

$\xi_0=\frac{2\hbar V_f}{\pi E_g}$

Penetration depth

$\lambda _L=\sqrt{\frac{m}{\mu_0nq^2}}$

Type $(II)$ superconductor

Characteristics value of London penetration depth and coherent length

$$\frac{\lambda}{\xi_0}=\frac{1}{\sqrt2}=0.707$$

$\frac{\lambda}{\xi_0}=0.707<1$

Option (3) is correct option