Question

A superconducting material has a critical temperature of 4.1 K at zero magnetic

field. The critical field at 0 K is 0.04 Tesla. Determine the critical field at 2 K.

Answer 1

$$H_c=H_0\left(1-\left(\frac{T}{T_c}\right)^2\right)\\ H_c=0.04\left(1-\left(\frac{2}{4.1}\right)^2\right)=0.03\ T$$